Table 3 (Continued)

CHICAGO 41.83N 272633E ILLINOIS
IGY TYPE NEUTRON MONITOR
FIFTEEN-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 18» 1968

TIME MINUTES AT END OF INTERVAL
Usles 15 30 45 60
800- 900 546 561 549 544
900-1000 546 546 558 538
1000-1100 544 570 547 567
1100-1200 562 542 558 555
1200-1300 562 550 555 534
1300-1400 566 553 562 545
1400-1500 571 563 558 540
1500-1600 553 549 554 549
1600-1700 552 554 558 555
1700-1800 560 567 547 538
1800-1900 557 564 548 553
1900-2000 556 551 549

SWARTHMORE 3B9e90N 284665E PENNSYLVANIA

NEUTRON MONITOR NM-64

CORRECTED FOR PRESSURE USING THE GALACTIC PRESSURE COEFFICIENT ONLY
SCALING FACTOR = 100

TWO-MINUTE HOURLY RATES

NOVEMBER 18s 1968

TIME MINUTES AT END OF INTERVAL
00 02 04 06 08 lo 12 14 16 18 20 22 24 26 28
OR 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58

1030 1053 1014 1053 1044 1044 1045 1046 1009 1038
1100 1067 1038 1076 1037 1047 1075 1056 1084 1056
1130 1046 1036 1055 1046 1063 1054 1044 1053 1053
1200 1043

1068 1087 1096 1087 1077 1076
1028 1027 1055 1065 1017 1046
1025 1044 1044 1061 1052 1024

KIEL 54e33N 10610E GERMANY
NEUTRON MONITOR 18-NM~64
REAL COUNTS 10 TIMES TABULATED COUNTS
FIVE-MINUTE BAROMETER CORRECTED RATES
NOVEMBER 18% 1968

TIME MINUTES AT END OF INTERVAL

Uele 05 10 15 20 25 30 35

900-1000 4682 4651 4672 4706 4685 4701 4659
1000-1100 4646 4620 4671 4650 4601 4614 4714
1100-1200 4715 4661 4708 4697 4685 4689 4706
1200-1300 4683 4668 4699 4653 4745 4725 4707
1300-1400 4715 4715 4686 4630 4710 4709 4648
1400-1500 4652 4641 4666 4642 4679 4697 4645

59

40 45 50 55 60

4714 4663 4704 4643 4664
4740 4674 4642 4712 4758
4715 4752 4629 4696 4757
4680 4645 4636 4753 4632
4637 4666 4620 4732 4674
4699 4675 4699 4668 4676



DATE SOLRAD 9 X-RAY MEMORY DATA a

10
881117
ad - spe pe aan el _ 1045
1h oy bee pee | et cle Aes “ol [Noh fke| cts beech lf
3-10) - aaa id
: 107 , Nez se TM a kat oh ia ‘- “ : ina \ Lh my fa ic
16 ; ~~ 7 ole
3 ol \hy il fou t tt ; hn f u ie | ee
CUCL ICO OCI UTE
a a 6 i 1203 MH 1S 1 TF ie 19 2 2 23 4

Fig. 3. . Solar X-ray Emission November 17, 1968.

Instead, the traces show that charged-particle interferences endured for approximately 20 to
30 minutes throughout the day. The charged-particle interferences during the first half of the day
lasted longer than those observed at similar times on November 17 and 18, Satellite orbit data
show that the longer duration charged-particle interferences occurred, because, after the flare,
the satellite encountered interfering charged-particles at lower altitudes and closer to the South
Pole between 50° and 180° East longitude. The additional particles encountered were probably high
energy protons coming directly from the sun and not trapped particles. The effect is not clearly
discernible on the plots prior to about 16 hours after the proton flare started. However, it is
quite possible that the increased proton flow began before it first becomes noticeable, because,
during the time intervening between flare occurrence and the clear evidence of increased charged-
particle interference, the satellite's path did not cross regions where differences in preflare and
postflare conditions in the southern hemisphere would be noticeable in the SOLRAD data. Changes in
the North Polar region were not observed, because the satellite usually crossed these regions dur-
ing periods of satellite night when the data memory system was not operating.

REFERENCES

KREPLIN, R. We. 1961 Ann. Geophys., 17, 151-161.

25



Solar and Interplanetary Phenomena,

WORLD DATA CENTER A

National Academy of Sciences
2101 Constitution Avenue, N. W. Washington, D. C. U.S.A., 20418

World Data Center A consists of the Coordination Office

and eight subcenters:

World Data Center A
Coordination Office
National Academy of Sciences
2101 Constitution Avenue, N.W.
Washington, D.C., U.S.A, 20418
Telephone (202) 961-1404

Meteorology (and Nuclear Radiation):

Ionospheric Phenomena, Flare~Associated World Data Center A:
Events, Aurora, Cosmic Rays, Airglow: Meteorology
World Data Center A: National Weather Records Center
Upper Atmosphere Geophysics Asheville, North Carolina, U.S.A, 28801
Environmental Science Services Telephone (704) 253-0481
Administration
Boulder, Colorado, U.S.A, 80302
Telephone (303) 447-1000 Ext. 3381 Oceanography:
World Data Center A:
Oceanography
Geomagnetism, Seismology, Gravity and Tsunami: Building 160
World Data Center A: Second and N Streets, S.E.
Geomagnetism, Seismology, Gravity & Tsunami Washington, D.C., U.S.A. 20390
Environmental Data Service, ESSA Telephone (202) 698-3753

Rockville, Maryland, U.S,'A. 20852
Telephone (301) 496-8160

Rockets and Satellites:
World Data Center A::

Glaciology: Rockets and Satellites
World Data Center A: National Academy of Sciences
Glaciology 2101 Constitution Avenue, N.W.
American Geographical Society Washington, D.C., U.S.A, 20418
Broadway at 156th Syreet Telephone (202) 961-1404

New York, New York, U.S.A. 10032
Telephone (212) 234-8100

Upper Mantle Project:
World Data Center A:

Longitude and Latitude: Upper Mantle Project
World Data Center A: Lamont Geological Observatory
Longitude & Latitude Palisades, New York, U.S.A, 10964
U.S. Naval Observatory Telephone (914) 359-2900 Ext, 209

Washington, D.C., U.S.A, 20390
Telephone (202) 698-8422

Notes:

(1) World Data Centers conduct international exchange of geophysical observations in accordance
with the principles set forth by the International Council of Scientific Unions. WDC-A is established
in the United States under the auspices of the National Academy of Sciences,

(2) Communications regarding data interchange matters in general and World Data Center A as a
whole should be addressed to: World Data Center A, Coordination Office (see address above),

(3) Inquiries and communications concerning data in specific disciplines should be addressed to

the appropriate subcenter listed above.

|



“Asymptotic Directions of Approach Appropriate for the High Energy
Solar Proton Eyent of November 18, 1968"

by

M. A, Shea and D, F, Smart
Air Force Cambridge Research Laboratories
Bedford, Massachusetts

Recent results of Gall [1968] and Gall, et al. [1969] show that the external magnetic sources
in the magnetosphere have an appreciable effect on the asymptotic directions of high latitude sta-
tions. As a result of the longitudinal asymmetry of the magnetosphere, it becomes apparent that
for precise analysis of cosmic-ray data acquired by high latitude neutron monitors the asymptotic
directions should be calculated as a function of local station time. In this paper we have calcu-
lated the asymptotic directions of approach for selected high latitude neutron monitors for rigid-
ities appropriate to high energy solar cosmic-ray events, All calculations were made for the local
station time equivalent to 1100 Universal Time - the time of maximum cosmic-ray intensity as record-
ed by neutron monitors for the solar cosmic-ray event on November 18, 1968.

The basic computer program of McCracken et al, [1962] where a charged particle of specified
momentum per unit charge is traced from a specific location outward through a magnetic field using
the Runge-Kutta method of integration, was modified [J. Jimenez, private communication] to include
the Williams and Mead [1965] expressions for external sources. The fields from these external
sources were vectorily combined with the field of the internal sources as specified by the Inter-
national Geomagnetic Reference Field, Epoch 1965 [IAGA Commission 2, Working Group 4, 1969].

The magnetic field B employed for the calculation of particle trajectories is derived from

B= By + BS + Bog

where

3

= the internal field,

= the external field due to currents in the magnetopause, and

Bog = the external field due to the current in the neutral sheet of the magnetospheric tail.

The internal field is obtained by

B= WwW

where the magnetic potential V is obtained by a spherical harmonic expansion

V(r,8,9) eel

a . = (er cos mp + wt sin mp) PY cos @ (8/r)

no

with a being the average radius of the earth, a. and nt the coefficients of the internal magnetic
field, and r the distance from the geocenter.

The following expressions were used for calculating the external fields:
= -! <1 -
B, = (8, cos 0 - 23%, (2/a) sin @ cos @ cos 1) 8,

0
+ @, sino -¥3

+3 £, (/a) cos 6 sin t ey»

2 (ela) 2 cos” @=1) cos 1) =

i)

with the values used for the coefficients of the external field sources being z = -0.2515/(r,%),

gi 70 1215/(x#) gauss, and
2

Bos = G,, sin 8 cos T - B cos 8)e. + @,, cos @ cos T + BY sin 8)eg + CB sin Dey

where

= -2j @, - 6),

= 2j log (r)/r1),
68



VICTORIA, CANADA

Geographic Latitude
Geographic Longitude

UT = 1100

Rigidity
(cv)

20,00
15.00
10.00
5.00
400
3.00
2.90
2.80
2.70

Ge & & & bo bo bo bo tn bo bo
& BRR

VSSSIss

LT = 0246
Geomagnetic Time

= 48.50 N
= 123.42 W
= 0237
Asymptotic
Lat Long
11,05  ~96.81
1.07 -98.34
~6.96 -100.30
-27.65 -78.56
-29.04 -68.62
28.44 ~32.01
~26.55 -28.84
2h 54 725 41
722.4 ~21.12
-19.70  -14.96
15.00 6.22
6.35 5.29
7.10 19.38
22.23 40,32
27.92 81.30
26.81 87.80
25.02 95 .08
22.32 103.10
18.41 111,93
12,84 121,97
5.09 133.14
~5 42 146.90
-14.64 169.66
23.49 87.16
222.99
349.58
152.31
373.25
383.50
304.60
346.40
327.56
R
R
368 Abe
F
F
182.52
R
229.74
352.52
381.18
R R
F R
R R
-9.89 375.08
R R
R R
R R
R R
F F
-8.94 364.04
F F
F F
F F
F F
F F
F F
F F
R R

79

Geographic Latitude

Geographic Longitude
UT = 1100

LEEDS, ENGLAND

Geomagnetic Time = 1157

Rigidity
(cv)

20,00
15.00
10.00
5.00
4,00
3.00

BULL LUN RRR RRR WWHwWWwHWbw PL

FURISSS IAS ERAN SOSALGSEHRIOOGSO

1.96
1.95

= 53
= 1
LT = 1054
Asymptotic
Lat Long
26.14 47,24
14.74 49.34
4.20 51.01
“10.94 82.39
“11.33 97.14
-1.84 144,02
3.40 151.32
89h 155.22
23.72 158.11
26.91 174.75
17.64 196.26
4.56 243.61
24.02 298.75
5.20 58.88
2.09 330,05
5.72 156.43
13.31 381.70
18.12 122.00
8.69 108.47
16.82 183.83
F F
R R
R R
R R
R R
22,18 73-40
18.41 69.63
R R
0.42 203.70
~4.93 330,93
F F
20.11 111.30
-13.87 308.68
7-40 396.36
-1.26 372.30
R R
6.56 395.01
12.78 55.66
R R
R R
14.56 132.75
73.71 395.74
R R
F F
-18,50 240.53
F F
R R
~6.22 252.47
R R
R R
R R
R R
F F
R R
F F
F F
R R

28:
35!

2
5 Ww



a BP ESSERREE & ERP Bg Eas
g

Fy Fy i $ z gS
3 8 8 g 3 3:
2
g
~ <<
: _ | ;
z = = z
gi fe 8 MPS GaP Poa eg CAR Gs ae
a 8 as
z z : 4 é
8 z : : : 1 §
= = 3 =
———s| =a at
:
i :
EY & Sp

noo 1130 1200 1000 1030 100 130 2200
ur — ur —

1030

000

HHI-records of the radio event of November 18, 1968.

Fig. la and lb.

15


CAPE SCHMIDT, USSR

Geographic Latitude - 68.87 N

Geographic Longitude - 179.49 W

UT = 1100 LT = 2302

Geomagnetic Time = 2155

Rigidity Asymptotic

(gv) LAT LONG

20,00 40.43 151.92
15.00 34,00 -156.61
10,00 30.13 -161.86
5.00 15.55 164.48
4,00 13.14  ~164.89
3.00 5.72 -171,30
2.00 2.64 ~180.54
1.50 -11.40  -174.08
1.40 -11.42  =173.80
1.30 -10,18 -169.83
1,20 8  -169.33
1.10 165.99
1,00 = 162.67
0.90 -162.00

74

APATITY, USSR

Geographic Latitude - 67.55 N
Geographic Longitude - 33.33 E
UT = 1100 LT = 1313
Geomagnetic Time = 1429
Rigidity Asymptotic
(cv) LAT LONG
20.00 47.26 71.32
15.00 41.62 69.86
10,00 37.98 68.46
5.00 24.17 78.17
4,00 22,44 81.96
3.00 13.31 87.44
2,00 2.91 101.23
1.50 -8.82 118.62
1.40 123.19
1.30 132.18
1,20 141.20
1.10 158.08
1,00 180.61
0.99 180.70
0.98 178.97
0.97 177.59
0.96 176.21
0.95 174.86
0.94 173.52
0.93 172.13
0,92 170.53
0,91 168.74
0.90 166,02



“Energetic Proton Flux (5-70 Mey) at Synchronous Orbit Noyewber 11 ~ Decemher 8, 1968"

by

G. A. Pavlikas
Space Physics Laboratory
The Aerospace Corporation, Los Angeles, California

The data in Figure 1 on the 5-70 Mey proton flux were obtained aboard the ATS-1 satellite.
The 21-70 Mey flux at this orbit appears to be identical to the interplanetary flux. The 5-21
Mey flux departs in a complex way from the interplanetary flux because the measurement is made
inside the magnetosphere, The flux may be attenuated by up to a factor of 10 for measurements
near local noon and magnetic quiet. For other local times and disturbed magnetic conditions the
flux of 5-21 Mev protons measured at ATS-1 approaches the interplanetary flux.

The measurements were made with an omnidirectional spectrometer. This instrument contains

shielded solid state detectors, Pulse height analysis discriminates electrons from protons and,
together with the shield thickness, determines the energy bites of the instrument.

32



Upper Atmosphere Geophysics Report UAG-1

“IQSY Night Airglow Data" by L, L. Smith, F. E. Roach, and J, M. McKennan of Aeronomy Laboratory,
ESSA Research Laboratories, July 1968, single copy price $1.75.

Upper Atmosphere Geophysics Report UAG-2
"A Reevaluation of Solar Flares, 1964-66" by Helen W. Dodson and E. Ruth Hedeman of McMath-
Hulbert Observatory, The University of Michigan, August 1968, single copy price 30 cents.

Upper Atmosphere Geophysics Report UAG-3

“Observations of Jupiter's Sporadic Radio Emission in the Range 7.6-41MHz, 6 July 1966 through
8 September 1968" by James W. Warwick and George A. Dulk, Department of Astro-Geophysics, Uni-
versity of Colorado, October 1968, single copy price 30 cents.

Upper Atmosphere Geophysics Report UAG-4
“Abbreviated Calendar Record 1966-67" by J. Virginia Lincoln, Hope I. Leighton and Dorothy K.

Kropp of Aeronomy and Space Data Center, Space Disturbances Laboratory, ESSA Research Laboratories,
January 1969, single copy price $1.25.

Upper Atmosphere Geophysics Report UAG-5
“Data on Solar Event of May 23, 1967 and its Geophysical Effects" compiled by J. Virginia Lincoln,
World Data Center A, Upper Atmosphere Geophysics, ESSA, February 1969, single copy price 65 cents.

Upper Atmosphere Geophysics Report UAG-6
"International Geophysical Calendars 1957-1969" by A. H. Shapley and J. Virginia Lincoln, ESSA
Research Laboratories, March 1969, single copy price 30 cents.

Upper Atmosphere Geophysics Report UAG-7
“Observations of the Solar Electron Corona: February 1964 - January 1968" by Richard T. Hansen,

High Altitude Observatory, Boulder, Colorado and Kamuela, Hawaii, October 1969, single copy price
15 cents.

Upper Atmosphere Geophysics Report UAG-8
"Data on Solar Geophysical Activity October 24 - November 6, 1968" compiled by J. Virginia Lincoln,
World Data Center A, Upper Atmosphere Geophysics, ESSA, March 1970, single copy price $1.75.

|



Acknowledgements

I thank T. E. Graedel for discussions of the data and C. M. Soltis for computational assistance.
The Alert neutron monitor data was kindly supplied by World Data Center A, Upper Atmosphere Geophys-
ies, Boulder, Colorado. .

REFERENCES
AXFORD, W. I. and 1963 J. Geophys. Res., 68, 1793.

G. C. REID

BRYANT, D. A., 1965 Astrophys. J., 141, 478.

T. L. CLINE,

U. D. DESAI, and

F. B, MC DONALD

LANZEROTII, L. J. and To be published.

T. E. GRAEDEL

LANZEROITI, L. J, 1969 IEEE Trans. Nucl. Sci,, NS-16(1), 343.
H. P. LIB, and

G. L. MILLER

LANZEROTII, L. J. and 1969 Solar Phys., 10, 212.

M. F, ROBBINS

RAO, U. Re, 1967 J. Geophys. Res., 72, 4325.

K. G, MC CRACKEN, and

R. P. BUKATA

39



"Scintillation Monitor Bologna, Italy 15-Minute Observations"

by

M. Galli
Istituto di Fisica "A, Righi"
Universita Degli Studi di Bologna

Figure 1 presents for November 18-20, 1968 the total ionization (T), the atmospheric pressure
at ground level (P), the soft component (M), and the hard components: 45° inclined towards West
(NW); 45° inclined towards East (E) and vertical cubical coincidences (V).

Table 1 presents the data from the scintillation monitor at Bologna. The tabulated data
should be read with a decimal point after the second figure of each number. The numbers are
deviations in % units from a fixed value of pressure corrected data at the end of each 15-minute
interval.

NOVEMBER 1968

T
|

Percentage Deviations

18 (323) 19 (324) | 20 (325)

Fig. 1. Scintillation monitor data November 18-20, 1968 at Bologna, Italy.

64



The fast time resolution data (not shown) indicates that all of the proton energy channel
counting rates increased at approximately the same time (+~10 minutes), The counting rates in-
creased rapidly to a peak and then decreased to a minimum approximately seven to eight hours after
the onset. The fluxes in the higher energy channels increased after the initial peak and then de-
creased steadily while the fluxes in the lower energy channel continued te increase steadily until
the time of the sudden commencement. It is interesting to note that an initial peak in the proton
fluxes after the particle onset was also observed after another extreme west hemisphere solar flare
on 10 September 1961 [Bryant et al., 1965].

After the sudden commencement the fluxes in all proton channels decreased. ‘Iwo subsequent
enhancements were seen prior to a rather steady, exponential decay of the fluxes. The time con-
stant of this decay, beginning at approximately 1200 UT on November 21, was approximately independ-
ent of proton energy [Lanzerotti and Graedel, to be published].

DAY , 1968, UT
322. 323, 324325326327
: T : r : 7

10? 18 q
E ! eae J
tole 4
¢ r nucl q
* ok :
Ps

La

10-16 Mev MO

AS
Mev. 4
1.6-2.2 SES q

_ 2 nucl. a -

p j 1
zl Wn alg
vo a 98

{ vy

=|2 a q10} 3/2
S Mi Bs 5
7 2.2-3,0 Mev. ®
2 nucl. 8
3 ®
“ “
i= E
2 a . a 2
2 MM os g
<

=x x
a Mev. a

4.0-6.0——-
2 nucl. a

3

=
}

P4

MeV
0-11.
6 Srucl. Nh,

fo}
‘

i
r

5
~

z

a
a
4

Sy
c
\
é
(
i"

a
fe]
T

17 18 19 20 2 22
NOVEMBER, !968, UT

Fig. 2. Alpha particle data following the 18 November 1968 solar flare.

35



Fig. 1. Cosmograms for the period November 16 to 22, 1968. Note the flare
increase at 1100 UT on November 18.

67



Table 1 (Continued)

13 14 15 16 17 18 19 20 al 22 23 24 AVERAGE

3999 3996 3979 3972 3955 3975 3980 3968 3976 3976 3966 3975 3968
6502 6465 6469 6419 6446 6461 6430 6414 6428 6432 6433 6424 643765
20435 20442 20447 20354 20291 20387 20241 20383 20380 20389 20321 20420 20348.9
1903 1903 1909 1921 1919 1931 1919 1921 1923 1919 1925 1919 1903
8559 8541 8546 8534 8535 8522 8514 8536 8521 8494 8436 8424 8472

2081 2063 2045 2047 2056 2049 2023 2025 2026 2022 2019 2026 2040

6143 6086 6083 6063 6041 6061 6063 6070 6076 6063 6053 6069 605606
5670 5644 5656 5624 5621 5640 5614 5636 5631 5627 5633 5638 562266
6299 6233 6219 6208 6225 6237 6202 6231 6226 6232 6228 6230 6211.2
475 468 489 480 488 491 495 495 481 477 466 482 1482.0

3344 3353 3349 3327 3351 3335 3346 3347 3342 3341 3331 3329 333066
6228 6189 6152 6137 6133 6116 6082 6076 6106 6092 6111 6121 6125.8
2610 2639 2612 2620 2629 2629 2567 2640 2610 2621 2663 2599 261543
10228 10170 10174 10145 10130 10112 10100 10096 10067 10041 10049 10103 10074.7

29 24 11 27 22 13 27 13 16 20 8 28 19.7

7623 7587 7558 7562 7505 7498 7473 7454 7456 7416 7466 7448 746600
1748 #1732 1731 1745 1740 1749 1744 1740 1744 41758 41759 1763 1739
2086 2050 2026 2037 2018 2006 2011 2031 2020 2028 2038% 2008* 2026
2338 2300 2300 2323 2295 2280 2294 2300 2291 2297 2300 2312 23021
1023 1006 988 1028 1004 1002 995 1002 1003 1010 1018 1003 1004

2204 2229 2234 2208 2223 2218 2226 2211 2199 2211 2178 2198 2201.7
6065 6064 6074 6095 6085 6080 6066 6070 6032 6022 6028 6030 6012.2
3130 3095 3110 3114 3091 3101 3079 3099 3094 3082 3094 3093 3098

6572 6537 6560 6547 6556 6597 6575 6577 6562 6559 6597 6563 6553.0
5609 5613 5601 5625 5609 5629 5614 5630 5637 5634 5639 5645 5613.9

3450 3452 3449 3457 3453 3466 3466 3472 3473 3483° 3488 3477 B457
3659 3656 3645 3653 0000 0000 3645 3600 3596 3603 3620 3618 3624.9

22 51 32 30 58 49 43 40 28 29 46 42 3607
4858 4850 4897 4898 4937 4896 4893
4521 4526 4548 4549 4568 4591 4528

5775 5780 5773 5772 5743 5709 5689 5708 5741 5763 5767 5760 5746.0
53890 54005 54814 54631 54314 54556 54566 54808 54602 55237 55168 54999 545569
5235 5286 5248 5289 5225 5221 5206 5139 5159 5230 5189 5232 5214
932 934 936 935 926 934 927 929 936 940 938 947 93349

2278 2280 2280 2281 2286 2289 2289 2288 2296 2297 2312 2314 2285

162 137 165 226 185 183 170 183 192 180 155 169 162.3
1566 1566 1604 1608 1620 0000 0000 0000 0000 0000 0000 odo00 1566
2169 2158 2157 2158 2161 2182 2159 2177 2189 2145 2142 2170 2155
2687 2744 2792 2753 2767 2814 2831 2842 2830 2797 2791 2817 277601
3584 3544 3537 3564 3664 3679 3666 3650 3682 3681 3680 3677 3658

6510 6512 6517 6521 6536 6528 6553 6555 6566 6573 6577 6586 653609
1194 1196 1189 1188 1187 1203 1190 1184 1192 1180 1182 1189 1188.3
1682 1672 1681 1677 1682 1674 1686 1688 1693 1686 1699 1688 1682.5

45



RINNERT, K.

LANGE-HESSE, G. and
K, RINNERT

1967

1969

REFERENCES

Die Beeintrachtigung transpolarer Langstwellenausbrei-
tung durch die solaren Protonen- und Plasma-Nieder-
schlage am 3./4. September 1966, Kleinheubacher
Berichte, Band 12, 261-264.

The reliability of transpolar VLF-measurements as a
method to forecast HF-propagation disturbances, AGARD

Conference Proceedings No. 49.

87



Table 2

SOLAR RADIO EMISSION
OUTSTANDING OCCURRENCES

NOVEMBER 1968

STARTING TIME OF RATION FLUX DENSITY
IGN, | FREQUENCY STATION | TYPE TIME waxtauy | 0m Hz wt REMARKS
UT UT MINUTES PEAK MEAN
18 9400 TYKW 5 0327 032942 6 Ted 240
8800 MNL 4 035967 040165 367 3903 1907
4995 MNL 4 035967 0401.5 37 Bed 4G
c 8800 MNL 0403.4 1366 1563 403
4995 MNL 26040 4h 165
c 8800 MNL 4e2 1 43
4995 MNL 4e2 1303 50d
9400 TYKW 5500 1060
3750 TYKW 2040 320
2695 MNL 909 343
2000 TYKW 500 200
8800 MNL 5003 2400
4995 MNL 4340 2067
17000 TOKO 1540
C 8800 MNL 1301 202
4995 MNL 1168 B05
200 GORK 7520
100 GORK 40600
9100 GORK 1 207
9139 NEUS .
719000 SLOU 26 1970-0
9500 NERA 31
}- 9139 NEUS 15 U 26000
}- 9100 GORK 35.5 297000 91060
} 3100 CRIM 160 77000
- 225 HARS 25 375200 6060U
}-15000 KISV 3405 275500U 815-0U
}- 6100 KISV 1045 3865 94540 43.0U
+ 3000 NERA 102967 40 140060 60040
}- 2950 GORK 1027490 37e3U 72060
f+ 2950 GORK 102967 92060
-- 2950 GORK 1044.8 82560
+ 2920 BERL 102965 214 U
F 2800 SLOU 102965 22 122060
F 1500 NEUS 1030 210 D 1091.0
}- 1420 KIEL 1031 4a 90040 35060
fF 930 BORD 102944 66 120020 6920 SLOW DECLINE
}- 808 ONDR 3495
}- 650 GORK 103204 35 54060
f 650 GORK 1040.5 17200
je 420 KIEL 1029 67 400200 30060
f- 260 ONDR 34 85400
+ 240 KIEL 1030 24 15000.0D 600.0
}- 234 POTS 103165 174 200040 18.0
+ 200 NERA 103261 9 35000 1500.0
f+ 200 GORK 103261 9e2 4000200
+ 111 POTS 1034 U 5105 8000-0 6000
+ 100 GORK 1034e2U 60 100000-0D
+ 100 GORK 1034.2 9el 100000.0D
|. 536 ONDR 1034 75 3250
1 202 IZmMI 1032 9 2000-0 300.0
;- 100 GORK 1049.1U 5009 270000
br 23 POTS 1048 U 25 4000.0 1200.0
}- 9139 NEUS 1044.5 195060
+ 2920 BERL 1044.5
+ 1500 NEUS 1044.5 28400
}- 2800 SLOU 1048 114 550+0
19000 SLOU 1052 UU 60 16000
f 3800 GORK 75 €
9500 NERA 73
3000 NERA 274 OD 6520
9100 GORK 16 7300
1500 BERL 6 le?
260 ONDR 1
1500 NEUS 10 led
15400 SGMR Tel 568
F 4995 SGMR 16 Bed
8800 SGMR 209 560
2800 OTTA 110 205
2800 OTTA 205 del
2800 OTTA 3 17



FOREWORD

This report is one of a series of special data compilations and discussion on solar-
terrestrial events of special interest, and collects in one place more data and more detailed
data than normally appear in the scientific literature. Cosmic ray increases at sea level are
relatively rare phenomena and there has been an informal consensus among cosmic ray scientists
that such a compilation should be made for the event of November 18, 1968.

Actually this report is an outgrowth of the preceding one in this series, UAG-8 "Data on
Solar-Geophysical Activity October 24 - November 6, 1968." That report was compiled to fulfill
a recommendation of the Inter-Union Commission on Solar-Terrestrial Physics and was the result
of the more than 50 replies providing detailed data or discussions of observations. In these
replies, many cosmic ray workers in particular included data and discussion through November 18,
commenting that this was a very significant phenomenon and from the standpoint of their disci-
pline much more interesting than the phenomena associated with the solar activity of the preced-
ing weeks. Rather than have UAG-8 include data and discussions on the November 18 event from
some authors but not others, it was decided to prepare this separate report from this volun-
teered information supplemented by the results of a new request to the other contributors to
UAG-8.

This is a truly international effort as can be seen by the list of contributors, acknowl-
edgment of whose participation is implicit. The solar-terrestrial scientific community is in-
debted to the compilers and editors of this report, the staff of World Data Center-A, Upper At-
mosphere Geophysics, Miss J. Virginia Lincoln, Director. The provision of these special data
reports, however, is still an experiment in communication within the scientific community and
the reactions of the community to this approach will determine the future course of these
efforts.

A. H. Shapley, Chairman
IUCSTP Working Group 1,
Monitoring of the Solar-
Terrestrial Environment





MAWSON, ANTARCTICA

Geographic Latitude ~- 67.
Geographic Longitude =~ 62
UT = 1100 LT = 1512

Geomagnetic Time = 1246

-60 S
88 E

Rigidity Asymptotic
(ev) LAT LONG
20,00 39.82 60.63
15.00 36.81 54.02
10.00 ~39.21 4B .W
5.00 727.59 52.19
4,00 -28.89 54.20
3.00 -20.76 53.38
2,00 14.73 58.00
1.00 5.85 68,28
0.90 9.46 70.98
GOOSE BAY, CANADA
Geographic Latitude ~ 53.33 N
Geographic Longitude - 60.42 w
UT = 1100 LT = 0658
Geomagnetic Time = 0743
Rigidity Asymptotic
(sv) LAT LONG
20.00 35.27 =20.69
15,00 27.02 — -20.16
10.00 19,96 “22.99
5.00 7.88 -13.64
4,00 6.06 = ~12.23
3.00 -2.61 ~5.22
2.00 ~10.17 7.27
1.50 717.79 24.06
1.40 -18,27 27.85
1.30 19.36 34.96
1.20 -19.59 42,13
1.10 -19.41 54.33
1.00 16.26 68.81
0.90 75.27 99.50

73

UT = 1100

Rigidity
(ev)

20.00
15.00
10.00
5.00
400
3.00
2.00
1.50
1.40
1.30
1.20
1.10
1,00

SYOWA, ANTARCTICA

Geographic Latitude - 69,03 $
Geographic Longitude - 39,60 £
LT = 1338
Geomagnetic Time = 1124
Asymptotic
LAT LONG
~35.59 46.34
~29.83 39.78
-29.27 31.36
-16.18 38.35
-16.56 36.46
5.38 40.87
3.60 44.76
12.77 53.32
18.72 56.43
19.22 57.70
24.92 63.97
26.56 67.71
33.18 77.70
38.14 93.84

0.90

TIXIE BAY, USSR

Geographic Latitude - 71.55 .N
Geographic Longitude - 128,90 £
UT = 1100 LT = 1936
Geomagnetic Time = 1909
Rigidity Asymptotic
(ev) LAT LONG
20.00 51.46 166.94
15.00 45.93 164.48
10.00 4.73 160,62
5.00 33.26 161.69
4,00 32.23 162,31
3.00 27.98 158.95
2.00 23.95 154.10
1.50 24.05 145.96
1.40 24 45 145.08
1,30 -24,28 145.61
1,20 732.35 151.78
1.10 -35.74 160.39
1,00 -35..74 171,30
0.90 -31.82 181.58



References

Baird, G. A. G. G.’ Bell, S. P, Duggal, and M. A. Pom.
erantz, 1967. Neutron monitor observations of high-
energy solar particles during the new cycle. Solar Physics,
2: 491-50

Pomerantz, M. A. and S. P. Duggal. 1961. Unusual in-
crease in the cosmic ray intensity on November 20, 1960.
Journal of the Franklin Institute, 271: 327-335.

Pomerantz, M. A., S. P. Duggal, and K. Nagashima. 1961a.
Observations near the North’ and South Poles of bursts
of cosmic rays from the sun. Journal of the Franklin
Institute, 271: 317-326.

Pomerantz, M. A., 8. P. Duggal, and K, Nagashima. 1961b.
Solar-produced cosmic rays near the North and South
Poles. Physical Review Letters, 6: 123-125,

Pomerantz, M. A., S. P. Duggal, and K. Nagashima. 1961e.
‘The unusual cosmic ray intensity increases on November
12,1960. Space Research, Il: 700-802,

Pomerantz, M. A. and S, P. Duggal. 1962. Anisotropy in
solar particles incident on polar regions during July 1961.
Journal of the Franklin Institute, 273: 242-248,

Pomerantz, M. A. 1968. Investigations of cosmic ray in-
tensity variations in Antarctica. Antarctic Journal of the
U.S., TH(5); 252-253.

ANTARCTIC JOURNAL

Reprinted from Antarctic Journal of the United States, vol. IV, no. 5.

82



REPORT UAG -9

WORLD DATA CENTER A

Upper Atmosphere Geophysics

DATA ON COSMIC RAY EVENT

OF NOVEMBER 18, 1968
AND ASSOCIATED PHENOMENA

April 1970





5. SPACE OBSERVATIONS

"Editorial Comments"
by

J. Virginia Lincoln
Space Disturbances Laboratory
ESSA Research Laboratories, Boulder, Colorado

In Report UAG-8 two of the articles included data for the period of this report, These were
"Explorer 35 University of California Energetic Particles Experiment October 26 - November 22, 1968"
by Robert B. Lin, and "Response of Electrons (Eg 20.28 Mev) at 1.2 SL <1.3 to the November 1968
Magnetic Storm" by J. C. Armstrong, C. 0. Bostrom and D. S. Beall. The former paper presents data
for >45 kev electrons, >22 kev electrons, >0.3 Mev protons and 215 Mev protons together with the
galactic cosmic ray background levels. The latter paper presents data for the count rates of elec-
trons 20.28 Mev at L= 1.2, A general feature of these electrons in this region of space is their
response to even modest geomagnetic activity.

30



"Radio Propagation Quality Indices November 15-30, 1968"

by

B. Beckmann
Fernmeldtechnisches Zentralamt
Deutsche Bundespost, Darmstadt, G.F.R.

The table presents radio propagation quality indices prepared from observations of the trans-
mission frequency ranges at three azimuths for both day and night radio propagation conditions.
The observations were made at Lichow 53.0°N, 11.2°E from selected transmitters located in the
three areas: U.S.A., South America and East Asia. ‘he only evidence of disturbance following the
November 18 proton event is the slight decrease in quality, which does not reach storm level, for
the night of November 19, A quality index of "6" represents normal conditions and values less
than "6" are indicative of disturbance.

Radio Propagation Quality Indices

derived from observations of the transmission frequency range

November 1968

USA South America East Asia
Date - Germany - Germany - Germany
Day Night Day __Night Day __Night
L 3.0 2.0 5.0 4.8 5.4 4.0
2 3,2 2.8 5.0 4.2 4.2 4,2
3 3.2 2.0 4.6 3.8 5.0 4.0
4 4.2 2.4 4.6 4.4 4.8 5.0
5 3.8 3.0 5.0 3.8 5.0 3.8
6 4.6 4.0 5.8 5.2 5.4 4.8
7 4.4 4.2 5.2 5.0 5.4 5.0
8 4.8 3.8 5.4 5.6 6.4 5.8
9 4.8 3.8 5.2 4.6 6.2 4.6
10 5.0 4.8 5.2 5.8 5.6 4.6
i 6.0 4.6 6.0 5.0 6.6 5.6
12 5.6 4.0 5.2 5.0 6.2 5.0
13 5.8 5.4 5.4 6.0 6.2 5.4
14 6.2 5.4 5.8 5.8 6.4 5.4
15 6.6 7.0 5.8 5.6 6.2 5.0
16 7.2 8.0 6.2 6.2 5.6 6.4
17 5.6 5.0 5.4 6.0 5.4 5.6
18 4.6 4.4 5.2 4.6 5.6 5.0
19 6.2 5.0 6.0 4.8 5.4 5.0
20 7.0 6.4 6.6 7.0 6.6 6.4
21 6.6 6.8 7.0 7.4 6.4 5.6
22 6.8 7.0 7.2 6.2 6.4 5.8
23 7.8 7.8 6.8 6.4 6.6 5.6
24 8.2 9.0 6.2 6.2 7.4 6.8
25 8.2 9.0 7.4 7.6 6.6 5.8
26 8.0 7.6 7.4 7.6 6.2 6.2
27 7.6 7.6 7.0 7.2 7.0 6.8
28 7.0 6.8 8.0 7.2 6.4 7.2
29 8.0 7.6 6.8 7.0 6.2 5.6
30 7.0 6.6 6.6 6.4 6.4 5.2

89



Table I - Event Onset Times on 18 November 1968

Event Onset Time (UT)
Flare 1030 E (in progress)
SCNA 1024

Type II 1026.5

Type IV 1026,5

Neutron Monitors 1045

ATS-I (Ep? 21 Mev) 1050

30 MHz Riometer

Absorption (McMurdo) 1055

Pioneer 8 (E)2 13.9 Mey) 1113

Pioneer 9 (E,2 13.9 Mev) 1116

According to Ktivsky and Svestka [1969], the main acceleration process occurs simultaneously
with the phase of the fast separation of the bright flare ribbons (which coincides with the hard
x-ray burst and the peak of the microwave radio flux), As this separation was observed to occur
between 1029 UT and 1031 UT, the propagation time for relativistic protons was about 16 minutes;
for protons of E70 Mey, approximately 21 minutes.

As is shown in the top half of Figure 1, 30 MHz riometer absorption could he identified to
commence at McMurdo Sound, Antarctica, at about 1055 UI. Due to the presence of Type IV solar
radio noise, an earlier time could not be determined, Shepherd Bay was experiencing day/night
effects. The McMurdo absorption increased very rapidly, reaching a first peak of 9.8 dB at 1224
UT, only 1.5 hours after onset. It then proceeded to drop to about 6 dB in 20 minutes, and then
rapidly increased to the maximum absorption of 12.5 dB at 1330 UI, Between 1330 UT and about
1900 UT, the absorption decreased from 12.5 dB to 6 dB, exhibiting large rapid fluctuations. The
magnetometer trace of the horizontal component exhibited the same rapid time variation but was out
of phase with the 30 MHz absorption by about 2 minutes, After 1900 UT the absorption began a grad-
ual increase, reached a broad maximum of about 8 4B, and began to decay at 1600 UT, 19 November,
reaching 1 4B at 2000 UT, 20 November. Three days later it returned to normal.

As can be seen in the lower half of Figurei1, the flux of protons of energies between 5 Mevs
E,S 21 Mev and 21 Mev< E,< 70 Mev, as observed by ATS-I [Blake, private communication], also ex-
nibited the same structure as the riometer absorption early in the event. ‘The peaks of the proton
flux profiles correspond with the riometer absorption peaks. These same variations were also ob-
served by K. A. Anderson's ionization chamber and scatter counter on IMP-E [private communication].

Acknowledgement

We are indebted to the Office of Antarctic Programs, National Science Foundation, for its
support of the work under Contract NSF C-393. This work was supported in part by the McDonnell
Douglas Independent Research and Development Program. We thank J. W. McDonough, G. C. Nelson, and
our station operators for their assistance in data reduction and overall program operation. Also,
we acknowledge the cooperation of the Canadian Government for allowing us to operate our northern
station.

REFERENCES
KRrvsky, L., and 1969 The Solar Proton Flares of June and November 1968 and
Z, SVESTKA February 1969, presented at the COSPAR Panel on Polar
Cap Experiments Meeting, Prague, May, 1969.
MASLEY, A. J., 1969 The 1968 Solar Cosmic Ray Events, Trans. Amer, Geophys.
J. W. MCDONOUGH, and Union, 50, 304.
G. C. NELSON

84



The November 18 flare can be added to Sakurai's list of flares with GLE in regions that showed
an anomalous orientation of the leader and follower polarities and that reached this configuration
by an apparent rotation that initially carries the leader spot to higher latitude. We can mention
some further examples that showed at least one of these conditions. The region of the flare of
1966 July 6 occurred along a line of polarity reversal that was nearly parallel to the equator,
with the spots of leader polarity on the poleward side. ‘This region included two bipolar pairs,
each born with the leader spot at higher latitude than the follower [Svestka, 1967]. The region of
1966 August gave a strong impression of rapid rotation [McIntosh, 1966]. From Sacramento Peak films
we estimate that the spots rotated through about 50° in the two days before the August 28 flare. The
triple flare of 1967 May 23 occurred in a region in which apparent rotation accompanied approach of
spots of opposite polarity [Mcintosh, 1969].

Negative examples, of changing anomalously oriented regions from which no energetic-particle
emission was detected, and of GLE flares not preceded by this behavior, are not hard to find. Fur-
ther study may determine whether the apparent rotation is itself important to acceleration and stor~
age of energetic charged particles, or if unusual orientation or great complexity of the sunspot
group is equally effective when achieved through development of new spots or through merging of
groups.

REFERENCES
HARVEY, J. W. 1963 Solar Magnetograph, Sky & Telescope, 26, 196-197.
LEIGHTON, R. B. 1959 Observations of solar magnetic fields in plage regions
Astrophys. J., 130, 366-380.
MC INTOSH, P. 1966 Private communication.
MC INIOSH, P. 1969 Sunspots associated with the proton flare of 23 May

1967, World Data Center A - Upper Atmosphere Geophysics
Report UAG-8, ESSA, Boulder, Colorado, 22-29.

RAMSEY, H. 1969 Detecting solar magnetic fields by filter photography
American Astronomers Report, Sky & Telescope, 37,
No. 6.

SAKURAI, K. 1967 Solar cosmic-ray flares and related sunspot magnetic

fields, Rept. Ionospheric and Space Res. in Japan,
21, 113-124.

SOLNECHNYE DANNYE 1969 Magnitnye polja solnechnyh pjaten, Akad. Nauk. SSSR.,
Noyabra 1968, Leningrad.

SVESTKA, Z. 1968 Proton flare, in Structure and Development of Solar
Active Region, K. 0. Kiepenheuer, ed., Springer-
Verlag, New York, 517.

THE AMERICAN EPHEMERIS 1968 U. S. Govt. Printing Office, Washington, D. C., 1966,
AND NAUTICAL ALMANAC 307.

12



Table 3 (Continued)

UNCORRECTED NEUTRONS, MONITOR

TIME UT,
000~ 100 27 pen 526 642 635
100- 200 634 626 625 638 640
200- 300 648 634 634 633 636
300- 400 639 638 622 631 647
400- 500 643 637 628 634 637
500- 600 634 632 639 628 643
600- 700 641 640 631 634 634
700- 800 642 635 646 623 636
800- 900 639 638 640 626 626
900~1000 641 642 641 649 636
1000-1100 645 636 647 636 648
1100-1200 719 692 684 694 681
1200-1300 674 664 665 666 667
1300-1400 664 676 667 670 658
1400-1500 662 668 672 655 674
1500-1600 669 678 675 670 663
1600-1700 0 677 682 668 671
1700-1800 665 673 672 673 665
1800-1900 668 663 669 655 662
1900-2000 668 672 676 681 652
2000-2100 677 665 658 665 675
2100-2200 674 655 653 662 654
2200-2300 661 650 tee 650 647
2300-2400 642 648 640 649
UNCORRECTED NEUTRONS, “oniTor D
000- 100 638
100- 200 eae baz 633 bat 649
200- 300 653 646 643 635 649
300- 400 642 639 638 632 632
400- 500 632 645 646 640 631
500- 600 637 642 627 650 647
600- 700 636 649 638 639 654
700- 800 636 645 632 632 625
800- 900 645 641 635 642 632
900-1000 634 648 644 654 644
1000-1100 648 646 656 653 650
1100-1200 729 692 703 686 698
1200~1300 673 672 684 666 676
1300-1400 681 683 680 675 676
1400-1500 677 681 678 659 683
1500-1600 668 677 676 658 678
1600-1700 OQ 683 682 683 668
1700-1800 674 681 701 678 675
1800-1900 684 687 672 673 672
1900-2000 670 673 675 682 688
2000-2100 674 688 684 679 666
2100-2200 661 663 659 655 645
2200-2300 673 eee 668 674 653
2300-2400 657 66 677 656 664
PRESSURE. iy MLLIBARS
000- 100 8856 8857 8857 8856
100~- 200 3858 8857 8856 8856 8855
200- 300 8855 8854 8855 8854 8854
300- 400 8852 8852 8852 8852 8853
400- 500 8852 8853 8854 8854 8854
500- 600 8850 8800 8850 8850 8850
600- 700 8850 8851 8851 8850 8848
700- 800 8847 8845 8845 8845 8844
800- 900 8842 8840 8840 8840 8840
900-1000 8836 8835 8835 8834 8834
1000-1100 8832 8832 8832 8831 8830
1100-1200 8826 8825 8825 8823 8822
1200-1300 8818 8817 8816 8816 8817
1300-1400 8812 8814 8810 8812 8810
1400-1500 8808 8809 8809 8808 8808
1500-1600 8805 8805 8805 8803 8802
1600~1700 0 8801 8799 8801 8800
1700-1800 8793 8793 8794 8793 8793
1800-1900 8793 8796 8798 8800 8798
1900-2000 8794 8794 8795 8795 8795
2000-2100 8800 8802 8801 8800 8802
2100-2200 8808 8813 8816 8817 8817
2200-2300 8818 8819 8821 8822 8823
2300-2400 8830 8832 8834 8835 8836

MINUTES AT END OF INTERVAL
30 35 40 45 50

636
640
633
647
630
652
650
628
638
637
634
688
674
669
669
666
670
658
676
676
663
654
643
655

644
634
639
650
638
642
634
647
647
655
637
701
671
666
681
676
672
682
675
681
668
657
658
653

8857
8856
8853
8853
8850
8851
8848
8844
8841
8834
8830
8820
8818
8811
8807
8802
8799
8793
8798
8794
8803
8816
8821
8837

54

632
636
630
631
629
633
633
640
638
643
632
681
667
678
666
678
661
677
678
684
668
667
650
655

647
637
640
641
635
645
645
641
641
663
648
685
668
681
669
671
667
689
678
695
675
664
669
659

8857
8856
8850
8853
8852
8850
8848
8843
8841
8833
8829
8822
8817
8811
8808
8801
8798
8794
8795
8794
8803
8816
8823
8837

627
618
647
627
629
625
630
638
639
637
647
659
673
671
673
673
677
670
673
667
656
658
660
643

631
640
648
631
631
639
636
634
650
654
651
687
679
673
682
674
684
679
678
682
669
665
660
656

8857
8856
8852
8853
8852
8851
8848
8843
8841
8834
8829
8821
8817
8810
8806
8801
8796
B794
8797
8794
8804
8817
8825
8838

627
634
642
639
637
644
635
629
652
641
643
678
684
659
670
680
679
687
676
677
663
650
648
659

642
651
649
638
644
642
637
643
633
654
650
674
683
671
680
680
690
670
675
690
661
659
652
653

8857
8856
8852
8853
8851
8851
8849
8843
8840
8833
8828
8820
8815
8811
8806
8801
8795
8790
8795
8796
8807
8817
8827
8838

637
635
636
627
634
627
639
631
639
643
676
683
660
672
678
664
667
669
675
668
667
659
657
640

633
643
640
630
637
646
647
644
648
644
688
685
680
660
690
682
680
673
680
678
669
673
661
650

8858
8850
8852
8852
8849
8850
8849
8842
8840
8833
8828
8820
8816
8811
8805
8801
8794
8791
8796
8796
8806
8818
8828
8839

55
617
644
643
638
630
634
630
648
647
651
743
677
672
652
677
677
682
685
659
672
650
661
653
651

637
645
649
642
645
647
643
640
648
650
760
664
680
671
671
682
689
673
692
679
664
660
662
660

8857
8855
8852
8853
8851
8850
8849
8842
8839
8833
8828
8819
8817
8809
8806
8801
8790
8793
8794
8798
8807
8819
8827
8840

60
621
629
644
634
631
638
614
644
631
649
729
680
667
689
660
664
676
677
670
661
653
661
654
644

645
650
646
630
653
645
644
641
643
657
742
681
679
685
674
677
689
685
682
680
662
659
665
653

8857
8855
8852
8852
8850
8851
8848
8841
8838
8832
8827
8819
8815
8808
8806
8800
8793
8794
8794
8800
8809
8819
8831
8842



COLLEGE en EI c=
SODANKYLA ee

LEIRVOGUR a NN AA A py
GREAT py etetnttl a
WHALE

RIVER | 07
ME ANOOK ea marten

oo 02 04 O06 08 lo 2 14 16 18 20 22 24
16 NOV 1968, HOURS, UT

Fig. 2b. H-component magnetic records of five high latitude stations for
November 16, 1968.

HONOLULU

KAKIOKA Mn eae

TANGERANG
|=»

TASHKENT ENN ace
M'BOUR

SAN JUAN

L 1 i 1 i 1 1 1 1 1 1 1 J
00 02 04 O6 08 10 12 l4 16 18 20 22 24
17 NOV 1968, HOURS, UT

Fig. 3a. H-component magnetic records of six low latitude stations for
November 17, 1968.

96



OULU, FINLAND

Geographic Latitude

- 65,00 N

Geographic Longitude - 25.40 £
LT = 1242
Geomagnetic Time =

UT = 1100

Rigidity
(ev)

20.00
15.00
10.00
5,00
4,00
3.00
2.00
1.90
1.80
1.70
1.60
1.50
1.40
1.30
1,20
1.19
1.18
1.17
1.16
1.15
1.4
1.13
1.12
1.1
1.10
1,09
1208
1.07
1,06
1,05
1,04
1.03
1,02
1.01
1.00
0.99
0.98
0.97
0.96
0.35
0.9
0.93
0.92
0.91
0.90

1357

Asymptotic

LAT

42.85
36.16
31.56
16.54
14.77
4,23
-5.98
-8.47
“11.31
~12,07
712.74
-15.30
~14,90
-13.90
711.21
-11,85
12.59
“13.52
-12.18

LONG

65.26

64,14

62.54

74.64

78.31

86.81
106,19
110.91
116.19
120.36
126.47
137.10
146,92
161.47
172.28
171.10
169.75
168,14
167.69
166.90

75

DEEP RIVER, CANADA

Geographic Latitude - 46.10 N
Geographic Longitude - 77.50 W
UT = 1100 LT = 0550
Geomagnetic Time = 0616

Rigidity Asymptotic
(cv) LAT LONG
20.00 21.85 -41.20
15,00 12.76 -40 4
10.00 4.65 = ~42.00
5.00 710.73 28.06
4.00 ~13.17 -23.98
3.00 =21.55 -9.20
2.00 21,69 21.14
1.90 20.47 28.80
1.80 -17.82 37.51
1.70 ~13.62 4h, 23
1.60 -8.79 52.93
1,50 2.72 71.26
1.40 20.10 98.96
1.30 16.69 162.29
1,29 -15.04 174.13
1.28 6.64 214,72
1.27 ~8.24 184.75
1,26 -8.31 170.94
1.25 20.28 183.78
1,24 TAL 172.75
1.23 8.30 162.06
1.22 23.17 182.01
1,21 R R
1.20 R R
1.19 -2.70 221.10
1,18 ~14,12 214.60
1.17 3.58 339.18
1.16 426 221.62
1.15 ~A.47 187,40
1.14 -2.05 177,02
1.13 9.87 208.99
1,12 R R
111 5.37 208.48
1.10 16.78 175.82
1,09 R R
1,08 8.11 210.16
1.07 R R
1,06 5.54 = 208.42
1.05 F F
7.47 1.04 398.34
-9.99 1,03 290.23
F 1,02 F
5.35 1,01 397.39
-18.94 1.00 210,20
2.66 0.99 281.28
R 0.98 R
F 0.97 F
17.47 0.96 170.82
R 0.95 R
R 0.9% R
F 0.93 F
R 0.92 R
F 0.91 F
R 0.90 R



Alpha Particle Observations

The hourly average alpha particle fluxes measured following the 18 November flare are plotted
in the Figure 2. The onset times of the alpha particles were also approximately energy independ-
ent and equal to the proton onset times. With the major exception that the initial particle peak
following the onset appears narrower for the alphas than for the protons, the general flux-time
profiles for the alphas and the protons are similar. The approximately exponential decay times
beginning on 21 November were approximately energy independent and equal to the proton decay times
[Lanzerotti and Graedel, to be published].

The alpha to proton ratios for particles compared as to equal energy (equal rigidity), equal
energy per charge (Eq = 2Ep) and equal energy per nucleon are plotted in Figure 3. For protons
and alphas of equal energy, the alpha to proton ratios increase steadily to the time of the sudden
commencement. Following two subsequent enhancements of the ratios, corresponding to the two flux
enhancements observed in all energy channels on November 20 and 21, the equal energy ratios re~
mained approximately constant, indicative of the energy-independent decay times beginning on 21
November.

The constant energy per nucleon alpha to proton ratios (vy = v,) decreased steadily from the
flux peaks following the particle onsets to the time of the sudden Gommencement. After an initial
enhancement in the ratios following the particle onsets, the constant energy per charge alpha to
proton ratios were essentially constant during the entire period when the particles were observed
at the earth.

The alpha to proton ratio data of Figure 3 suggests that the initial enhanced spike of par-
ticle fluxes following the particle onsets at the earth was enriched with alpha particles from the
flare. Following this enhancement, however, the three sets of alpha to proton ratios had time be-
haviors quite similar to those observed following the east hemisphere solar event of 23 May 1967
[Lanzerotti and Robbins, 1969]. These similarities and their implications for solar particle
propagation are included in a paper in preparation [Lanzerotti and Graedel, to be published].

02 I

Mev

6 Mev 0.08} 2 Mev cost 5 Mev
R=107 MV 2 nucl. yy 3G

a 004 004

on

:

|
i

ne

in

2

5
2
S

&

8 Mel
os 123 MV Lv 8 ev. ~ pels A
= 2 nuck G
ga £ o08 Fo
2 od Mm + 008
2 ry :
S oz! | 2 004 2
3S Mev 2 nw & 04
& 18 MV - So O, °
x Ot = F eo
B = 004+ 4 Mev =
| 3 Mey S008
3 Tee
¢ z 0, + 004 AN
© 02 i 3 g
2 12 Mev ¥ 2
2 % 0041 . Mev in zo,
on ¢ 2 0.08
iy Eo Lennon fil z
oO < 0.04
0044 . Mev ir pay
02 fel [Paley 9
as t avsl ev
: 004} 5 Mev 004
nucl. pan
° fa kee er ot. | M4
20 21 22 7 18 19 20 ef 22 7 1 19 20 2 22

NOVEMBER, 1968, UT

Fig. 3. Alpha to proton ratios plotted as a function of equal particle energy, equal
particle energy per nucleon and equal particle energy per charge.

36



TIME
00
OR 30

1030 1292
1100 2361
1130 1330
1200 1308

TIME
Uele

Table 3

THULE T6e55N 2914¢16E GREENLAND

NEUTRON MONITOR NM-64

CORRECTED FOR PRESSURE USING THE GALACTIC PRESSURE COEFFICIENT ONLY
SCALING FACTOR = 100

TWO-MINUTE HOURLY RATES

NOVEMBER 18% 1968

MINUTES AT END OF INTERVAL

02 04 06 08 10 12 14 16 18 20 22 24 26 28
32 34 36 38 40 42 44 46 48 50 52 54 56 58
1272 1272 1302 1331 1292 1262°1272 1282 1321 1292 1292 1302 1371 1390

1366 1390 1420 1351 1390 1369 1369 1359 1359 1359 1310 1320 1340 1300
1350 1320 1330 1350 1320 1369 1319 1319 1299 1309 1329 1279 1338 1299

ALERT 82630N 62+20W CANADA
NEUTRON MONITOR 18-NM-64

REAL COUNTS 100 TIMES TABULATED COUNTS
FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES
NOVEMBER 185 1968

MINUTES AT END OF INTERVAL
05 10 15 20 25 30 35 40 45 50 55 60 AVERAGE

900-1000 6351 6364 6441 6351 6467 6396 6409 6487 6422 6312 6376 6428 6400

1000-1

100 6441 6422 6435 6422 6370 6331 6422 6383 6396 6422 6429 6500 6414

1100-1200 6746 6888 6584 6636 6539 6571 6636 6597 6577 6539 6448 6545 6609
1200-1300 6513 6461 6532 6545 6455 6506 6487 6519 648) 6513 6474 6526 6501
1300-1400 6526 6410 6500 6481 6532 6513 6500 6436 6397 6391 6513 6397 6466
1400-1500 6474 6487 6442 6532 6365 6442 6468 6474 6525 6474 6519 6391 6466
1500-1600 6468 6430 6398 6385 6449 6372 6430 6462 6430 6379 6430 6391 6419
1600-1700 6468 6474 6423 6417 6417 6481 6500 6442 6455 6430 6430 6442 6448
1700-1800 6449 6449 6563 6461 6487 6461 6392 6430 6461 6423 6525 6449 6462
1800-1900 6436 6430 6487 6417 6455 6506 6455 6442 6335 6379 6392 6392 6427
1900-2000 6404 6430 6385 6461 6335 6385 6474 6461 6411 6487 6373 6348 6413

2000-2

100 6360 6411 6499 6436 6360 6474 6367 6480 6436 6385 6455 6467 6427

2100~2200 6411 6411 6455 6442 6455 6392 6430 6385 6448 6461 6430 6423 6429
2200-2300 6373 6537 6392 6411 6436 6436 6385 6354 6493 6430 6404 6505 6430
2300-2400 6417 6455 6367 6448 6360 6423 6423 6461 6461 6423 6423 6442 6425

TIME-HRe

9-10
lo-11
11-12
12-13
13-14

RESOLUTE T4e7ON 94e98W CANADA
NEUTRON MONITOR 6-NM-64

FIVE-MINUTE BAROMETER CORRECTED RATES

NOVEMBER 185 1964

MINUTE AT END OF INTERVAL
5 10 15 20 25 30 35 40 45 50 55 60

17167
17012
17342
17218
17195

16898
17001
17996
16727
17460

17283
16656
17747
17099
17319

16703
16699
17681
17087
17051

16778
17267
17434
16967
16795

16855
16593
17637
17032
16997

48

16745
16604
17422
17247
16847

17056
16849
17240
16990
16591

17036
16892
17090
17001
16792

16886
16612
17207
16947
17026

16682
16849
17229
17151
17375

16552
17877
17154
16938
16897



TIME
UeTe

000~
100-
200-
300-
400~-
500-
600-
700-
800-

Table 3 (Continued)

CALGARY 51e08N 2454¢91E

NEUTRON MONITOR 12-NM-64

CANADA

FIVE-MINUTE UNCORRECTED AND PRESSURE HOURLY RATES

NOVEMBER 18s 1968
UNCORRECTED NEUTRONS» MONITOR A

MINUTES AT END
05 10 15 20 25 30

100 650 633 636 647 625 636
200 630 654 638 638 639 657
300 638 634 631 636 637 637
400 640 645 636 645 630 638
500 635 639 646 637 643 643
600 645 645 643 639 644 635
700 640 648 630 640 643 637
800 652 647 647 637 634 645
900 651 639 635 637 652 643

900-1000 647 649 644 647 647 655
1000-1100 642 642 648 647 646 647
1100-1200 725 696 689 675 701 668
1200-1300 668 668 664 667 677 685
1300-1400 673 670 667 683 673 667
1400-1500 675 680 681 684 666 658
1500-1600 675 663 666 675 675 674

1600-1700

0 678 681 682 679 682

1700-1800 690 676 677 683 682 673
1800-1900 682 673 657 676 665 671
1900-2000 678 681 673 682 663 686
2000-2100 678 671 666 673 671 673
2100-2200 664 663 660 661 649 668
2200-2300 648 666 670 653 650 657
2300-2400 658 661 648 658 667 651

TIME
UsTe

000-
100-
200-
300-
400-
500-
600-
700-
800-

UNCORRECTED NEUTRONS» MONITOR B

MINUTES AT END
05 10 15 20 25 30

100 632 636 631 644 635 632
200 641 634 636 636 645 654
300 632 640 637 640 639 630
400 629 637 647 633 644 643
500 642 641 638 650 637 646
600 637 641 633 636 621 630
700 646 636 634 643 643 640
800 636 644 636 639 639 637
900 640 642 652 637 653 645

900-1000 644 649 648 644 648 645
1000-1100 641 659 660 648 652 652
1100-1200 717 702 687 690 690 680
1200-1300 678 661 668 679 680 676
1300-1400 666 676 681 681 686 665
1400-1500 683 663 673 672 669 675
1500-1600 672 680 674 670 688 687
1600-1700 0 666 664 676 675 668
1700-1800 685 672 675 665 682 678
1800-1900 679 674 681 681 679 673
1900-2000 674 689 676 673 676 674
2000-2100 676 660 670 672 660 656
2100-2200 662 660 668 659 661 670
2200-2300 653 667 648 664 663 665
2300-2400 651 660 663 658 653 660

8

OF INTERVAL

35

631
625
648
638
631
639
622
637
651
647
650
685
673
665
685
685
670
678
677
672
676
665
669
659

40

648
641
647
637
645
643
644
640
653
657
657
680
676
683
675
667
677
687
684
668
681
678
649
653

45

627
662
634
641
649
627
645
638
641
655
651
684
674
684
670
676
678
668
666
681
677
658
668
662

OF INTERVAL

35

650
631
647
639
631
633
645
632
640
643
656
677
672
675
679
670
670
674
677
672
669
664
655
661

40

636
631
647
621
633
645
633
643
641
657
644
683
675
664
680
674
681
670
673
665
665
655
649
646

45

637
639
632
637
644
647
633
646
642
652
655
676
674
667
675
668
683
682
667
680
673
663
661
650

50

644
636
632
638
634
635
626
640
641
644
687
675
666
657
678
676
684
678
671
671
667
679
664
659

50

647
637
629
652
629
645
629
638
646
642
686
682
668
660
677
686
671
682
681
680
677
662
656
667

55

641
642
640
632
645
638
655
641
648
649
751
673
667
665
678
676
683
679
696
665
676
$48
664
649

55

635
636
638
642
635
647
637
647
646
638
757
669
678
678
687
682
673
675
687
670
671
656
651
654

60

636
636
641
634
636
630
641
643
642
651
743
680
677
661
674
680
671
681
679
668
664
667
650
651

60

639
659
645
623
638
635
632
641
639
644
739
676
675
675
672
688
680
695
676
665
673
661
649
655



Table 3 (Continued)
DUMONT D'URVILLE 664665 140.02E — ANTARCTICA
NEUTRON MONITOR 9~NM-64
CORRECTED FOR BAROMETRIC PRESSURE
COEFFICIENT 969 PER CENT PER CM HG
MULTIPLY INDICATED NUMBERS BY 400
FIFTEEN-MINUTE HOURLY RATES

NOVEMBER 185 1968

TIME MINUTES AT END OF INTERVAL
UsTs 15 30 45 60
900-1000 230 226 228 227
1000-1100 227 227 225 236
1100-1200 241 235 235 233
1200-1300 232 231 230 229
1300-1400 230 231 229 230
MCMURDO 770858 166672E ANTARCTICA
NEUTRON MONITOR NM-64
CORRECTED FOR PRESSURE USING THE GALACTIC PRESSURE COEFFICIENT ONLY
SCALING FACTOR = 100
TWO-MINUTE HOURLY RATES
NOVEMBER 185 1968
TIME MINUTES AT END OF INTERVAL
00 02 04 06 08 10 12 14 16 18 20 22 24 26 28
OR 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58
1030 2812 2770 2855 2759 2824 2786 2750 2848 2813 2900 2886 3087 3089 3167 3123
1100 3020 3077 2970 2989 0000 2991 2947 2962 2917 2910 2917 2917 2892 2930 2903
1130 2940 2909 2924 2930 2924 2909 2930 2944 2930 2924 2868 2878 2892 2909 2851
1200 2847
SOUTH POLE 896985 0400E ANTARCTICA
NEUTRON MONITOR NM~64
CORRECTED FOR PRESSURE USING THE GALACTIC PRESSURE COEFFICIENT ONLY
SCALING FACTOR = 100
TWO~MINUTE HOURLY RATES
NOVEMBER 18> 1968
TIME MINUTES AT END OF INTERVAL
00 02 0 06 o8 lo 12 14 16 18 20 22 24 26 28
OR 30 32 «434 36 38 40 42 44 46 48 50 52 54 56 58
1030 670 667 646 688 678 668 657 688 699 720 782 835 824 814 815
1100 815 793 773 794 762 762 752 752 741 741 762 741 752 752 741
1130 752 721 741 731 710 721 710 700 721 700 700 742 690 000 000
1200 700

49



DURHAM, U.S.A.

BURHAM, U.S 2%
Geographic Latitude = 43.10
Geographic Longitude = 70.84
UT = 1100 LT = 0617
Geomagnetic Time = 0647
Rigidity Asymptotic
(cv) Lat Long
20.00 18.00  -29.37
15.00 7.58 -27.12
10.00 -2.14  =27.04
5.00 716.52 -5.79
4.00 -18.23 1.26
3.00 -20.66 27.39
2.50 -14.68 43.53
2.40 ~12.30 © 50.91
2.30 ~8.01 59.89
2.20 -1.60 68.87
2.10 5.39 77.28
2.00 12.04 87.86
1.90 21.51 110.83
1,80 25.73 164.57
1.79 21.23 165.19
1.78 11.98 164.73
1.77 “11.06 177.96
1.76 12.62 220.41
1.75 14,02 400.99
1.74 -13.05 199.46
1.73 12,82 181.15
1.72 -0.94 = 152.93
1.71 2.51 200.46
1.70 5.02 322.06
1.69 6.15 196.59
1.68 13.61 190.05
1,67 -6.93 212.76
1.66 R R
1.65 R R
1.64 R R
1.63 R R
1.62 -17.03 209.37
1.61 1,04 305.68
1,60 R R
1.59 23.06 185.43
1.58 3.03 181.72
1.57 ~24,85 212.80
1.56 -14.67 274.53
1.55 5.15 356.24
1.54 717.25 227.31
1.53 “17.86 364.47
1.52 5.78  195:00
1.51 5.97 299.24
1,50 7.87 214.37
1.49 R R
1.48 715.40 327.98
1.47 F F
1.46 -15.74 281.03
1.45 ~16.65 199.84
14 F F
143 F F
1.42 20.01 92.30
1.41 R R
1.40 F F
1.39 F F
1.38 F F
1.37 F F
1.36 9.07 109.00
1.35 -15.08 218.77
1.34 F F
1,33 F F
1.32 R R
1.31 F F
1.30 R R

az

78

CHICAGO, U.S.A,

Geographic Latitude = 41,83 N
Geographic Longitude = 87.67 W
UT = 1100 LT = 0509
Geomagnetic Time = 0529
Rigidity Asymptotic
(ev) Lat Long
20.00 11.54 ~51.57
15,00 1,21 -50.33
10.00 8.04 -50,40
5.00 ~ 24.29 -25.58
4.00 - 24.93 ~16.06
3.00 -21.56 16.76
2.90 -19.56 19.72
2.80 -17.40 22.64
2.70 15.04 26.27
2.60 712.23 31.27
2.50 8.03 38.56
2.40 -0.83 48.76
2.30 10.55 62.02
2.20 2422 81.37
2.10 31.08 114.67
2.00 15.33 148.05
1,99 12.61 153.27
1.98 14,63 178.94
1.97 16.14 216.29
1.96 6.42 148.16
1.95 14.73 59.52
1.94 2.77 197.99
1.93 14,37 197.41
1.92 ~8.22 206 85
1.91 7.16 197 Ab
1.90 18.77 176.41
1.89 13.76 189.55
1.88 R R
1,87 R R
1,86 9.87 88.31
1.85 R R
1.84 R R
1,83 5.69 188.06
1.82 -18.24 289.02
1.81 4.89 276.42
1,80 -23.80 246 63
1.79 ~467 - 188.34
1.78 ~1.81 342.24
1.77 - 13.83 305.52
1.76 R R
1.75 9.29 87.40
1.74 R R
1.73 “17.41 306.55
1.72 R R
1.71 R R
1.70 R R
1.69 F F
1,68 -8.59 321,03
1.67 F F
1.66 F F
1.65 F F
1.64 R R
1.63 F F
1,62 R R
1,61 R R
1.60 F F



"Ionospheric Absorption Around November 18, 1968”

by

}. Schwentek
Max-Planck-Institut fur Aeronomie, D 3411 Lindau (FRG)

The measurement of ionospheric absorption by field-strength recordings on the frequencies
2.61, 2.77 [Schwentek, 1966] and 6,09 MHz over paths of about 300 lua, and by a riometer, the cor-
ner reflector antenna of which is directed to the Pole star [Schwentek, in press], showed mainly
a sudden shortwave fadeout on November 18, 1968 as indicated in Table 1. The effect was very
strong so that during its maximum the signal strengths of 2.61, 2.77 and 6.09 MHz were zero (total
blackout). ‘The cosmic noise record was disturbed by a solar radio burst occurring for a certain

time interval during the fadeout.

Table 1

Characteristic data of the ionospheric effect (shortwave fadeout) on November 18,
1968 observed at Lindau (FRG; 51°39'N; 10°7.5'E). U = unreliable; N= value can-
not be determined; d = distance.

Start | Maximum | End | Type | Absorption | Frequency | Method | Remarks d

ur ur ur 4 L(aB) QmHz) en
1026] oN u1230 | s-swe | > 15 2.61 43 | total

blackout | 296

1026| WN 1206 | s-swr | > 13 2.77 A3 " 300

1027|  N 1224 | s-swr | > 25 6.09 A3 ” 339

1026) WN 1224 | S-SWF N 27.6 42 | partly -

(11002) 2.0) disturbed

With the exception of the quoted SID on November 18 (Table 1) the riometer showed no clear ef-
fect during the daylight hours. However, the data obtained in the interval 18-20, and 20-22 MET
(= Uf + 1h) indicate a small enhancement of absorption (Table 2) on November 18 to 20 (see also
Figure 1 in the contribution by K. Rinnert on page 86 of this Report.

Table 2

Mean absorption L(27.6 MHz) in dB with regard to the quiet day curve in the
interval 18-20 h and 20-22 h for the period November 15 to 26, 1968

Date Nov. 15] 16 | 17 | 18 | 19 | 20 [| 21 | 22 | 23 24 25 26

18-20 h | -0.05 0.10/0.05 40.14} 0.05|0.16] 0.04] 0.02/0.05}-0.06{-0.03 |-0.02

20-22 bh 0,02 0.08 |0.02 }0.13)0.09/0.08]0.03} 0.03/0.07] 0.06} 0.07} 0.03

REFERENCES
SCHWENTEK, H. 1966 Annales de Géophysique 22, 276-288
SCHWENTEK, H, and J. Atm. Terr. Phys., in press.

E. H. GRUSCHWITZ

88



6. COSMIC RAYS

"Tabulations and Selected Graphs of Neutron Monitor Observations November 18, 1968"

by

J. Virginia Lincoln
Space Disturbances Laboratory
ESSA Research Laboratories, Boulder, Colorado

One of the outstanding sea-level increases in cosmic ray intensity as observed by neutron moni-
tors was observed on November 18, 1968. Data pertinent to this event are reported.

The data presented were submitted to World Data Center A - Upper Atmosphere Geophysics in keep-
ing with routine submission of data, The cooperation of all the reporting observatories is grate-
fully acknowledged.

Table 1 presents the hourly values for November 18, 1968 from 43 stations listed in cutoff
rigidity order. In Table 2 the stations abbreviations are indicated together with equipment, coor~
dinates, cutoff rigidity, scaling factor, pressure to which corrected, pressute coefficient, mean
station pressure, and real count information for each reporting observatory.

Following these hourly values are given in Table 3 the two-minute, five minute, ten-minute or
fifteen-minute hourly rates during the period of the increase on November 18, 1968 from 23 stations.
All data are pressure corrected except for Calgary and Sulphur Mountain for which uncorrected and
pressure hourly rates are given. The headings of each station present the necessary details for in-
terpretation of the data. The stations are in cutoff rigidity order as follows:

Station Cutoff rigidity Hourly rate
Thule -00 Two-minute
Alert 0.00 Five-minute
Resolute 0.00 " "
Dumont d'Urville 0.01 Fifteen-minute
McMurdo 0.01 ‘Two-minute
South Pole 0.12 noo"
Inuvik 0.18 Five-minute
Fort Churchill 0.21 " "

Goose Bay 0.52 noon

Oulu 0.81 " "

Deep River 1.02 " "
Ottawa 1.08 Ten-minute
Calgary 1,09 Five-minute
Sulphur Mountain 1.14 uooM

Port aux Francais 1.19 Fifteen-minute
Mt. Washington 1.24 Five-minute
Durham 1.41 " "
Uppsala 1.43 ooo
Chicago 1.72 Fifteen-minute
Swarthmore 1.92 Two-minute
Kiel 2.29 Five-minute
Lindau 3.00 Ten-minute
Climax 3.03 Fifteen-minute
Dallas 4.35 Five-minute

A few selected graphs are presented following the tabulations. Figure 1 gives the Victoria
superneutron monitor pressure corrected data at five-minute intervals. A tabulation of these data
was not available.

Figure 2 gives detail of the onset of the increase as seen on the Deep River superneutron moni-
tor from 1000 to 1200 UT.

In Figure 3 the five-minute data from Goose Bay, Deep River, Inuvik and Alert are shown in per-
centage deviations for 0900-2400 UT.

43



WORLD DATA CENTER A

Upper Atmosphere Geophysics

REPORT UAG- 9

DATA ON COSMIC RAY EVENT
OF NOVEMBER 18, 1968
AND ASSOCIATED PHENOMENA

compiled by

J. Virginia Lincoln
WDC-A, Upper Atmosphere Geophysics

Boulder, Colorado

Prepared by Research Laboratories, ESSA, Boulder, Colorado Y
and published by “il

U.S. DEPARTMENT OF COMMERCE
ENVIRONMENTAL SCIENCE SERVICES ADMINISTRATION

ENVIRONMENTAL DATA SERVICE
ASHEVILLE, NORTH CAROLINA, USA 28801

April 1970

SUBSCRIPTION PRICE: $9.00 a year; $2.50 additional for foreign mailing; single copy
price varies.* Checks and money orders should be made payable to the Superintendent of
Documents. Remittance and correspondence regarding subscriptions should be sent to the
Superintendent of Documents, Government Printing Office, Washington, D.C. 20402.

“price of this issue 55 cents.



"Events of November 15 to November 22, 1968"

by

John F, Steljes
Atomic Energy of Canada Limited
Chalk River, Ontario, Canada

A figure presents the cosmograms from 1800 UT November 15 to 0600 UT November 22, 1968.

A cosmogram is a projection of the cosmic ray intensity as a function of the spatial angle
and time. The anti-solar direction is taken as 0° and the angle increases in the direction of ro-~
tation of the earth. The "garden-hose" angle lies between 90° and 180°.

The vertical thickness is proportional to the cosmic ray intensity, zero thickness being equal
to the lowest intensity attained by any station during the entire period covered by the cosmograms.
A scale of percent is given at the left hand lower corner. Time runs diagonally from the top right
to the bottom left of the figure and there is a 12-hour overlap between the adjacent cosmograms.

The paths of the stations are lines extending vertically downwards as is described in a pre-
vious publication [Carmichael and Steljes, 1969]. These paths have been omitted here because of
the small size of the cosmograms.

The stations used are as follows:

Station Operated by Asymptotic angle
Oulu Finland 4,31 hours
Tixie U.S.S.R. 10.66

Tnuvik Canada 15.70

Churchill, Canada U.S.A. 19.01

Goose Bay Canada 22.43

The stations are those of the "Northern Ring", five in all, and the angles between them are
filled in by linear interpolation between simultaneous readings at each station. ‘his type of
interpolation is valid if the event is assumed to occur simultaneously at each station as is the
case with a Forbush decrease. Each interpolation is judged to be valid for an angle of 30° (2
hours) on each side of the station (after rounding off to the nearest hour). If the separation is
greater than this, the intervening portion of the cosmogram is dotted. One dotted portion occurs
over Reykjavik and the other over Noril'sk, U.S.S.R.

After interpolation, the data are passed through a triangular filter in the time direction,
having weights 1, 2, 3, 2, 1 (operating on hourly values) in order to reduce statistical fluctua-
tions.

In Fig. 1 note the flare increase at 1100 UT on November 18. It was not observed at Oulu and
only slightly at Tixie, hence the gap in the "wall" representing the increase. The shape of the
"wall" gives a good idea of the way in which the interpolation between stations and the smoothing
in the time direction operate. All the cosmograms are on the same scale

REFERENCE
CARMICHAEL, H. and 1969 Forbush Decrease and Cosmogram May 25-26, 1967, Data
JOHN F, STELJES on Solar Event of May 23, 1967 and its Geophysical

Effects, World Data Center A, Upper Atmosphere Geo-
physics Report UAG-5, ESSA, Boulder, Colorado,

February 1969, 83-86.

66



DEEP RIVER

NEUTRON MONITOR

Table 3 (Continued)

46.06N 77+30W

48-NM-64

REAL COUNTS 300 TIMES TABULATED COUNTS

CANADA

FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 185 1968

10 15

6072 6090
6125 6095
6421 6355
6265 6247
6236 6172
6180 6174
6187 6135
6168 6102
6127 6127
6094 6073
6087 6113
6096 6043
6087 6087
6092 6113
6140 6119

MINUTES AT END OF INTERVAL

20

6102
6124
6297
6235
6217
6168
6124
6123
6126
6061
6075
6086
6102
6134
6129

2 IGY NEUTRON MONITORS

25

6102
6130
6291
6258
6195
6122
6169
6140
6109
6104
6101
6065
6033
6123
6083

45640N

30

6108
6136
6273
6211
6166
6116
6196
6112
6131
6038
6058
6080
6111
6083
6093

35

6155
6112
6297
6222
6154
6189
6106
6144
6093
6086
6105
6105
6101
6104
6108

75 060W

REAL COUNT 64 TIMES TABULATED COUNTS

TEN-MINUTE BAROMETER CORRECTED RATES

NOVEMBER 18% 1968

TIME
Uele 05
900~1000 6114
1000-1100 6101
1100-1200 6516
1200-1300 6224
1300-1400 6208
1400-1500 6237
1500-1600 6115
1600-1700 6164
1700-1800 6106
1800-1900 6105
1900-2000 6067
2000-2100 6060
2100-2200 6062
2200-2300 6117
2300-2400 6129
OTTAWA
TIME
UsTe

900-1000

1000~1100

1100-1200

1200-1300

1300-1400

10

8743
8905
91.9
91.7
B89

MINUTES AT END OF

20

876

1

8701
91e7
8903
8702

30

8606
8602

B96

0

8609
9003

52

40

6060
6106
6261
6257
6222
6144
6100
6165
6115
6097
6078
6074
6090
6093
6134

45

6113
6077
6279
6187
6199
6138
6100
6129
6152
6074
6061
6099
6117
6125
6144

CANADA

INTERVAL

40

86.0

87.
926

8
ie}

B76
9060

50

6084
6388
6237
6221
6170
6104
6104
6113
6108
6079
6051
6082
6096
6119
6138

50

55

6119
6809
6243
6209
6180
6133
6148
6113
6107
6094
6066
6110
6117
6098
6108

87.1
9003
9167
BB8e2
B6e7

6136
6715
6248
6169
6169
6110
6142
6156
6111
6056
6082
6087
6128
6119
6108

60

60 AVERAGE

6105
6243
6310
6225
6191
6151
6135
6136
6118
6080
6079
6082
6094
6110
6119

88el
9608
8904
8906
BBe4



HONOLULU

KAKIOKA IN

TANGE RANG

50y

TASHKENT ee

M'BOUR

SAN JUAN ae NR

L 1 i 1 1 1 i 1 L 1 1 L !
oo 02 04 O06 O8 10 12 4 16 Ig 20 22 24
21 NOV 1968, HOURS, UT

Fig. 7a. H-component magnetic records of six low latitude stations for
November 21, 1968.

COLLEGE Sane anne coneaeenenell
T

5007
1
SODANKYLA - ~
LEIRVOGUR ea ad
GREAT WHALE
RIVER
MEANOOK me aie

00 02 O04 O06 O8 10 2 \4 16 18 20 22 24
21 NOV 1968, HOURS, UT

Fig. 7b. H-component magnetic records of five high latitude stations for
November 21, 1968.

101



"Solar Cosmic-Ray Event on 18 November 1968"

by

Stephen Pintér
Geophysical Institute of the Slovak Academy of Sciences
Hurbanovo, Czechoslovakia

A sudden enhancement of cosmic radiation was observed at many terrestrial observatories on 18
November 1968. Cosmic-ray events were connected with the flare which appeared near west limb at
the position 18N 84W.

Most of the observatories classified the flare as one with importance 1b in the HO line. Ac~
companying phenomena such as the radio bursts in the different wavelengths, x-ray bursts and SID
effects connected with them show that it was a large energetic solar event. The relative low degree
of the importance of the flare in H&-line can be explained with respect to its limb position.

The flare appeared in McMath plage region 9760 which was visible on the solar disk from 4 No-
vember until 18 November. ‘he active region was created by a great group of spots with a configura-
tion typical of proton active regions. The maximum area of spots reached approximately 800-mil-
lionths of the hemisphere. According to "Solar-Geophysical Data”, there were 73 confirmed flares
in the studied region, none of which had greater importance than that of 18 November. Since the
proton eruption appeared close to the limb we can study the spatial evolution of the flare in con-
nection with the x-rays in more detail.

The cosmic-ray flare began in H& light at 1026 UT in the form of a mound. The evolution of
this limb phenomenon is visible on the sequence of the photographs from the HO Cinematographic
Flare Patrol made at the Cape of Good Hope Observatory, thanks to the Royal Observatory of England.

One minute after the commencement of the flare at 1027 UT there appeared an explosive phase,
during which the above cited mound suddenly expanded in the north-south direction along the limb.

In this manner an emission filament was created which had the form of a string of pearls (ac-
cording to Ktivsky) where each pearl had increased intensity. During the time from 1028 to 1033 UT
the "string of pearls" expanded moderately, and its intensity in HQ increased. At 1034 UT expan-
sion in the vertical plane began, i.e. one part of the flare went over the solar limb. Maximum of
the flare is ascribed to the time 1035 UT. On Figure 1 we can see the beginning phase of the sepa-
ration of the emitting region at 1040 UT meanwhile a flare channel was created in the center. We
can see the creation of the loop structure, Twenty minutes later, i.e. at 1100 UT, the expansion
and elevation continued meanwhile a very bright strand developed on the top of the loop structure
of the flare channel.

At about 1115 Uf the loop structure reached maximum intensity and maximum height. Then the
loop structure collapsed. A detailed study of this proton limb phenomenon was carried out by
Ktivsky and Svestka [1969].

As is seen, on the basis of the behavior of the flare in Ha-line, the most probable phase of
the acceleration process occurred during the time interval 1027-1035 UT. Figure,2 shows the time
intensity profile of the soft x-ray burst in the wave ranges 1 - 8 A and 8 ~ 20 A, respectively,
measured by the satellite Explorer 37 [Kreplin, 1968]. The beginning of the x-ray burst at 1026 UT
coincides with the time of the beginning of the HO flare.

Impulsive increase of the flux level 1 - 8 A and 8 - 20 A x-ray emission began at 1027 UT at
the time of the explosive flare phase and lasted to 1031 UT, i.e. 4 minutes. During thig interval
of 4 minutes, the flux level 1 - 8 A of x-ray emission increased from 7.7 x 10-" erg cmTM* sec"
to 3.4 x 10-! erg emm* sec-?.

The time of the implusive increase of the level of x-rays defines the acceleration time of the
particles in the flare region. Unfortunately at the time of the maximum phenomenon x-ray detectors
aboard Explorer 37 were saturated.

Very long exponential decay time (24 hours) of the soft x-rays, which is show in Figure 2, is
typical for the great bursts connected with proton flares.

During this solax cosmic-ray event a soft 2 - 12 A x-ray burst was registered by Explorers 33
and 35 [Van Allen, 1967]. The maximum flux F (2 - 12 A) = 0.25 erg cm? sec~! was recorded at 1057
UT after which followed a moderate decay of intensity.

‘The crochet (SFE) was observed at the Hurbanovo Observatory. ‘The beginning of the crochet was
at 1026 UT; the impulsive increase of the horizontal intensity of the geomagnetic field occurred
during the interval 1027 to 1030 UT. ‘his agrees well with the explosive phase and with the impul-
sive increase of the soft x-rays. 2%



*g96T “QT Teqmason ‘AXO}eATESGQ [POTWOUVOTISy aISeTIL ‘381nq 2H EEZ JO BSuToeTA uoTINTOSAT MOT

2 ‘8a

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Al

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22


"protons, Alpha Particles, and Electrons Resulting from the 18 November 1968 Solar Flare"

by

L. J. Lanzerotti
Bell Telephone Laboratories
Murray Hill, New Jersey

This report presents the data on the solar proton, alpha particles, and electron fluxes meas-
ured by an instrument on the Explorer 34 (IMP F) satellite following the extreme west hemisphere
(N21 W87) 1B solar flare of November 18, 1968. The Bell Telephone Laboratories instrument on Ex-
plorer 34 has been previously reported in the literature [Lanzerotti et al., 1969]. The data
measurements will be described below; a more complete discussion of the observations and their im~
plications for solar particle propagation is in preparation [Lanzerotti and Graedel, to be pub-
lished].

Proton Observations

Figure 1 contains the hourly average solar proton fluxes measured in the ‘eight energy chan-
nels of the experiment. Plotted at the bottom of the figure are the hourly counting rates of the
Alert neutron monitor. The ground level high energy particle enhancement from the flare is clear-
ly observed. Also indicated in the neutron monitor plot is the time of the sudden commencement
magnetic storm at 0904 UT on November 20,

DAY, 1968, UT Day, 1968, UT
324325326327, 322-323 3243253526 827
of

103 ' q
Le 44-50MeV 5
2b
056-060 Mev /\) 10" (¥ aa
o

/\ o6-1.2 Mev? tore

PROTONS (cm? sec ster Mev)"

ra mY 108 B10! |

tot 40?

alah, [neste
10 Pye“ NI 174-206 MeV. 410! i

83 Joo
25-4. MeV E ae -y10'
4 L MY!
68 sc 68} se
Peas s [ a
2 66p 66 \n |
ESN SI Oe cae Oe wee alana” VA Lamrtn“4
Ey | A] ALERT 1
8 e2r 1 62h J
7 8 © 2 a 2 7 6 © 2 a 2
NOVEMBER, 1968, UT NOVEMBER, 1968, UT

Fig. 1. Solar proton data following the 18 November 1968 solar flare. Plotted below
the proton fluxes are the hourly neutron monitor rates from Alert.

34



DURHAM

Table 3 (Continued)

43010N 289+16E

NEUTRON MONITOR NM~64

FIVE-MINUTE BAROMETER CORRECTED RATES

NOVEMBER 18»

MONITOR A
TIME
UsTs 05
900-1000 5691
1000-1100 5633
1100-1200 5925
1200-1300 5789
1300-1400 5755

MONITOR B
TIME
Usle 05
900-1000 5586
1000-1100 5424
1100~1200 5716
1200-1300 5476
1300-1400 5496

UPPSALA

NEUTRON MONITOR»

10

5644
5581
5794
5658
5640

10

5539
5528
5716
5423
5589

1968

15

5644
5732
5846
5627
5666

15

5434
5471
5690
5470
5408

MINUTES AT END

20

5565
5648
5846
5757
5718

25

5644
5539
5742
5725
5666

30

5670
5695
5716
5694
5449

MINUTES AT END

20

5539
5439
5559
5522
5563

59

25

5487
5460
5350
5595
5485

°85N

30

5460
5382
5611
5382
5526

1769:

OF IN
35

5623
5565
5565
5590
5707

NEW HAMPSHIRE

40

5623
5533
5710
5616
5604

TERVAL

45

5576
5695
5669
5720
5624

OF INTERVAL

35

5387
5486
5539
5564
5526

2E

40

5361
5585
5658
5564
5655

SWEDE!

SUM OF 2 NM~IGY SECTIONS

45

5471
5408
5486
5564
5547

N

BAROMETRIC COEFFICIENT IS 0.736 PER CENT PER MB

SCALING FACTOR 4

FIVE-MINUTE HOURLY RATES

NOVEMBER 18+ 1968

TIME
UsTe

000~ 100
100- 200
200- 300
300- 400
400- 500
500- 600
600- 700
700- 800
800- 900
900-1000
1000-1100
1100-1200
1200-1300
1300-1400
1400-1500
1500-1600
1600-1700
1700-1800
1800-1900
2900-2000
2000-2100
2100-2200
2200-2300
2300-2400

05

521
526
532
516
547
528
534
502
532
549
519
506
539
550
529
559
528
529
517
543
537
534
507
522

10

515
510
541
512
526
526
S11
528
486
536
527
530
560
522
548
560
505
524
518
524
535
534
534
524

15

522
524
501
525
538
542
504
521
532
542
509
524
518
512
533
542
509
509
523
542
530
529
549
535

MINUTES AT END

20

532
495
512
507
517
533
523
491
529
512
488
529
525
545
506
538
523
520
529
524
508
530
532
528

25 30
501 522
498 505
506 510
528 514
523 525
529° 515
517 530
527 507
524 503
522 534
506 520
534 534
532 537
502 522
550 532
523 555
533 547
558 502
526 508
508 522
539 529
503 522
526 511
520 524

58

OF INTERVAL

35

519
554
509
517
525
511
532
544
505
525
524
538
530
542
524
540
549
553
535
528
542
528
521
514

40

519
546
517
515
508
524
527
510
521
521
515
546
537
535
533
523
495
491
534
538
553
530
536
519

45

529
513
494
509
526
537
531
531
525
525
531
542
520
540
505
495,
524
508
527
531
527
524
537
536

50

5582
5826
5701
5584
5536

50

5476
5617
5622
5610
5562

50

534
493
543
517
506
523
525
534
565
548
506
538
513
530
541
495
529
549
550
508
528
523
502
518

55

5497
5904
5TT4&
5558
5608

55

5339
6087
5669
5532
5505

55

516
499
498
506
S11
527
526
546
536
529
538
540
525
501
551
532
541
515
545
511
534
498
504
527

60

5744
5716
5664
5475
5685

60

5429
5820
5455
5657
5453

60

525
534
517
535
539
531
534
519
523
522
517
521
523
513
528
542
472
563
517
507
538
531
520
531



SANAE, ANTARCTICA

SANAE ANTARCTICA

Geographic Latitude -
Geographic Longitude -

UT = 1100

LT = 1050

Geomagnetic Time = 0932

Rigidity
(cv)

20.00
15,00
10,00
5.00
4.00
3.00
2.00
1.90
1.80
1.70
1,60
1.50
1.40
1.30
1,20
1.19
1.18
1.17
1.16
1.15
1.14
1.13
1.12
1.11
1.10
1,09
1,08
1,07
1,06
1,05
1.04
1,03
1,02
1.01
1.00
0.99
0.98
0.97
0,96
0.95
0.9%
0.93
0.92
0.91
0.90

70.46 S
2.49 W

Asymptotic
LAT LONG
32.43 23.29
22.69 18.07
-15.43 8.72
72.07 19.25
5.00 17.92
14.18 28.87
31.80 53.72
31.90 57.36
31.24 61.34
32.96 70.99
33.68 88.42
28.96 100.90
23.53 117.15
-2.56 154,20
~4.70 182.46
6.80 181,02
18,07 200.63
~27.64 319.25
8.46 115.60
10.99 214,09
5.52 225.91
3.29 210,90
20.98 222.23
22.13 215.16
2.35 400,01
~27.59 299.40
8.54 210.24
11,86 211,18
-1.20 182.28
8.24 172.35
412 203.42
73.51 168.24
79.95 323.81
11.22 203.95
~6.55 379.06

F F
-7.28 199.56
2.77 363.90
75.11 347 45

F F
8.62 384,32
-0.28 194.69

F F

R R

R R

76

OTTAWA, CANADA

Geographic Latitude = 45.40 N
Geographic Longitude = 75.60 W
UT = 1100 LT = 0558
Geomagnetic Time = 0625
Rigidity Asymptotic
(ev) Lat Long
20.00 21.02 ~38.00
15,00 11.60 ~36.86
10.00 3.13 ~38.15
5.00 ~12.13 =22.70
4.00 ~1448 = 18.12
3.00 722.16 1.17
2.00 -18.30 33.23
1.90 “15.91 AD AA
1.80 -10.92 52.12
1,70 -3.87 61.30
1.60 3.90 73.31
1.50 22.33 109.01
1.49 24.57 116.19
1.48 26.40 124.10
1.47 27.53 133.21
1.46 27.75 142.56
1.45 26.92 151.
1 4b 24,83 159,91
143 21.84 167.47
1.42 25.26 166.70
1.41 22.35 164.55
1.40 16.46 161.67
1.39 8.59 158.18
1.38 9.80 184.68
1.37 0,95 = 231.32
1,36 R R
1.35 -18.12 224.20
1.34 -5.27 171.05
1,33 -8.07 257,14
1.32 5.42 168.99
1.31 -28.56 253.58
1.30 R R
1.29 R R
1.28 1.26 154.10
1.27 11.16 187.45
1,26 1.07 413.65
1,25 ~11.60 199.29
1.24 -12.40 213.80
1,23 F F
1.22 “7.22 190.17
1.21 -9.30 283.69
1.20 7.27 215.96
1.19 78.13 266.55
1.18 -2.19 174,34
1.17 4.71 200.98
1.16 R R
1.15 F F
V1 0.13 198.79
1.13 F F
1,12 78.18 361.70
mn -13.12 185,07
1.10 “12.81 332.88
1.09 w15.71 344.63
1.08 F F
1.07 -10,34 282.33
1,06 R R
1,05 R R
1.04 F F
1,03 F F
1.02 F F
1.01 F F
1.00 F F



°

Oooo
=
7
3 NOVEMBER 18, 1968
'g
& °
> 8-20A
SF ! 4
5
we
“t “al
§
o
10° 416"
. 2
1-8A 3
\ ”
§
2b
LE 40s
cr
—t
z
“ft
2
&
Fes a
1000 1100 12 00 13 00 14.00 15 00
UT

Fig. 2. Intensity profiles of soft x-rays 1 - 8 A and 8 - 20 A,
November 18, 1968 from Explorer 37.

Sudden increase of the intensity of cosmic-rays in the energy range 0.0 - 5.0 Bev began at
1040-1055 UT. We can see the time dependence between the beginning of the sudden increase of the
cosmic-ray intensity and the energy of cosmic rays in Figure 3. It is clear that the greater the
energy the shorter the time of arrival of the particles from the sun. Supposing that all the
particles are accelerated during the short time of the explosive phase of the flare we can judge
that the time of the arrival of the 4.4 Bev ray from the sun to the earth was 13 minutes and for
the 1.0 Bev, 18 minutes. The maximum intensity of cosmic-rays at the Deep River Observatory was
12%, observed at 1052 UT. After the maximum a very quick decrease of the intensity of cosmic-rays
followed.

In conclusion we can judge, on the basis of the obtained values, that the energetic particles
due to the x-ray burst in the different ranges and due to the increase of the solar cosmic-rays
are accelerated during some minutes, in the interval of the explosive phase of the flare. It is
obvious that the short interval of the impulsive increase of the x-rays is of non-thermal origin
after which follows thermal radiation.

Acknowledgements
The writer is greatly indebted to Professor C. W. Allen from the University of London Observa-

tory, England for the HO film of the event studied here and to Mr. D. H. Horan from the Naval Re-
search Laboratory for the material on x-ray bursts.

28


flare sighting is the most probable for a flare to produce identifiable si and ssc observed at the
surface of the earth; the average time is about 40 hours [Akasofu and Yoshida, 1967].

TrTTrTrrTrrrrr rr rrrrr rr rrr
+
soy

TrIrTrrrrTyy)

HONOLULU H

Sl, SSC 7 TEL ttt tC TEL RAH ttt t tt i
HPC 4,5—4
FLARES 7 “

i ee ee
00 06 la 18 24 06 12 18 24 06 12 Is 24

16 NOV 1968 17 NOV 1968 i8 NOV 1968
rTrTTTTTTrTrrrrrrrrrrr Ptr ttt rrr er tr rrr rd

wonoLuy HS SPT
1
Si, ssc fon t ot

FLARES l24

k Jt { i it jt u imi 4 al 4 Jijyeit u Jot 4 Jt 1 Joy oj pot } i yy
00 (06 12 18 24 (06 12 18 24 = (06 12 18 24
I9 NOV 1968 20 NOV 1968 21 NOV i968
HOURS, UT
Fig. 1.

The H-component magnetic record of Honolulu for the period November 16-21, 1968. ‘The major si
are indicated by arrows and reported ssc by triangles over arrows. Dotted and solid horizon-

tal lines represent the first 20 hours and the next 52 hours, respectively, after flares of
Importance 21 were observed.

The numbers from 1 through 27 identifying the flares are the
same as those in Table 2. 94



2. SOLAR REGION

Preceding Changes in the Active Region”
by

Constance Sawyer
Space Disturbances Laboratory
ESSA Research Laboratories, Boulder, Colorado

and

Sara F. Smith, Lockheed Solar Observatory
Rye Canyon Research Center of Lockheed
Saugus, California

ABSTRACT

The sunspot group that produced the flare of 1968 November 18 showed three features
that have been described as characteristic of energetic active regions: one part of the
region grew as another part seemed to decay [Martres et al., 1968]; the line of magnetic
polarity reversal lay nearly parallel to the solar equator; and the transition from the
normal, north-south orientation appeared as a counterclockwise rotation in this northern-
hemisphere region (Sakurai, 1967]. The polarity reversal line appeared to rotate by
about 30° per day from November 14 to 17.

The primary data used in this study are derived from Lockheed Solar Observatory's filter mag-
netograms. This technique for observing magnetic fields is described and illustrated by Ramsey
[1969] and is similar in principle to the methods employed by Leighton [1959] and Harvey [1963].
Briefly, the method of obtaining the magnetic field information is as follows. Half-second expo-
sures are taken through a filter having a bandpass of .15A centered .15A into the blue wing of the
Fel line at 53244. A 1/4 analyzer is rotated 90 degrees between successive frames of film ex-
posed at 10-second intervals. By this technique frames of film containing righthanded circularly
polarized light (negative polarity) are alternated between frames containing lefthanded circularly
polarized light (positive polarity). The intensity of the polarized component of light is related
to the strength of the line-of-sight magnetic fields. When the film is projected an obvious flick-
ering in intensity occurs at locations where the line-of-sight components of magnetic field are
strong. Areas of opposite polarity are readily distinguished because they flicker out of phase.
Lines where the flicker changes phase, therefore, correspond to the boundaries where the polarity
reverses. It should be noted that the intensity of the flicker varies greatly with changing image
quality and with distance from the center of the solar disk as well as with the strength of the
magnetic field components being observed. In this contribution, however, we are primarily concern-
ed with the qualitative use of these films for determining the configuratién of the line-of-sight
scomponents of the magnetic field rather than quantitative values of field strength.

| |
|
i

|
Low
I UN
1a \ ae aa oe “|
joer ps ny
Ss
| 11.20 | 1213 | 13,33 | 14.16 | 5.04! 16.04 lizos! 18.11 |

Fig. 1. Upper line: fhe sunspot group and magnetic fields as seen on filter magnetograms in the
period preceding the flare of November 18, 1968. Lower line: sunspot drawings and
magnetic fields from Solnechnye Dannye. The region is shown on successive days as it
rotated across the disk.



CALGARY, CANADA

Geographic Latitude = 51.08 N
Geographic Longitude = 114,09 W
UT = 1100 LT = 0324
Geomagnetic Time = 0317
Rigidity Asymptotic
(Gv) Lat Long
20.00 19.46  =90.17
15.00 11.40 -92.20
10,00 4,99 -94,86
5.00 -13.88 — -85.75
4.00 “17.02 -81 tl
3.00 -26.93 -70,58
2.00 -31.10  -38.63
1.90 -30.40 — -30.06
1,80 -27.90 --22.58
1,70 ~24.69  =16.78
1.60 ~20.29 ~6.30
1.50 -9.33 8.81
1.40 2.63 22.55
1.30 32.05 90.29
1,29 27.15 122.47
1.28 10.19 152.89
1.27 -19,06 146.53
1.26 Th.4O 202,72
1.25 -11.56 179.69
1,24 -23.90 282.13
1.23 w11.16 156,43
1,22 4.84 218.91
1.21 ~468 365.24
1,20 ~9.12 180.34
1.19 6.82 169.14
1.18 R R
1.17 75.52 215.36
1.16 72.05 429.57
VIS F F
1.14 12.46 170.17
1.13 wAM7 222.91
1.12 713.57 353.60
1 -2.15 375.72
1.10 ~5.35 284.00
1,09 5.58 300.33
1,08 721.14 290.99
1.07 ~5.38 391.11
1.06 F F
105 1.53 216,28
1.04 R R
1.03 R R
1.02 -10.09 322,24
1.01 F F
1,00 R R
0.99 F F
0.98 R R
0.97 F F
0.96 F F
0.95 F F

PORT AUX FRANCAIS

Geographic Latitude = 49,35 $
Geographic Longitude = 70.22 £
UT = 1100) LT = 1541
Geomagnetic Time = 1442
Rigidity Asymptotic
(cv) Lat Long
20.00 715.40 86.86
15.00 84.81
10,00 83.06
5.00 98.04
4,00 101.87
3.00 120.25
2.00 159.78
1,90 165.91
1,80 174.95
1,70 176.27
1.60 173.37
1.50 174.83
1.49 180.14
1.48 185.81
1.47 191.34
1.46 196.78
1.45 -7.06 203.32
1.44 -2.03 209.90
143 4,98 216.89
1.42 14.81 223.56
1.41 13.26 236.64
1.40 -2.38 © 252.48
1.39 7.15 334.54
1.38 234.60
1.37 418.87
1.36 300.38
1.35 359.69
1.34 406.50
1.33 R
1.32 327.57
1.31 392.31
1,30 R
1,29 R
1.28 395.44
1,27 261.22
1.26 307.06
1.25 296.53
1.24 364.71
1.23 254.86
1.22 358.99
1.21 F
1,20 207.99
1.19 AIA,B2
1.18 . 221.50
1.17 -10.47 232.03
1.16 -7.66 361.69
1.15 F F
1.14 F F
1.13 F F
1.12 F F
1 F F
1.10 F F

77



7. IONOSPHERE

“Observations in the Arctic and Antarctic of the 18 Noyember 1968 Solar Cosmic Ray Eyent"

by

A. D. Goedeke and A. J. Masley
Space Sciences Department
McDonnell Douglas Astronautics Company - Western Division
Santa Monica, California, U.S.A.

ABSTRACT

One of the largest solar proton events during the present broad solar max-
imum period occurred on 18 November 1968. The only visible flare that could be
associated with the particle emission was a 1B flare that was in progress at 1030
UT, 18 November, located at N22 W87 in McMath Plage Region 9760. Type IV radio
emission, of intensity 3, occurred between 1026 UT and 1034 UT. Type II emission
was present between 1026 UT and 1050 UT, At about 1045 UT, the Deep River and
Sulphur Mountain neutron monitors indicated an increasing counting rate, The
Sulphur Mountain super neutron monitor registered a 12% maximum increase at about
1052 UT; by 1130 UT, the counting rate was down to 4% aboye normal. The relativ—
istic particle intensity increase at ground commenced a few minutes before increased
counting rates were observed on VELA and the ATS-I satellites. The first increase
in the flux of 21< E,<.70 Mev observed by ATS-I occurred between 1050 UT and 1100 UT.
The 30 and 50 MHz riometers at McMurdo Sound, Antarctica, registered the onset of
polar cap absorption at about 1055 UT. The propagation time between the sun and
earth for Gev protons was about 16 minutes; for low energy protons, the delay time
was about 21 minutes. The peak 30 MHz absorption was 12.5 dB at 1330 UT.

Introduction

The solar cosmic ray event of 18 November 1968 was observed in space by particle detectors on
such satellites as IMP-E, 0GO-5 (1968-14A), ATS-I (1966-110A) and 1963-38C. It was also observed
by ground-based instruments, including neutron monitors and polar-based riometers, The riometer
data to be reported here were taken at the McDonnell Douglas Astronautics Company's (hereafter re-
ferred to as MDAC) Geophysical Observatories and were briefly discussed by Masley, et al. [1969].

The MDAC Antarctic Geophysical Observatory (77°51'S, 166°43'E) at McMurdo Sound began opera-
tion in February, 1962. The magnetically conjugate Arctic Observatory (68°49'N, 93°26'W) at Shep-
herd Bay, N.W.T., Canada, began operation in August, 1963. These stations, at geomagnetic lati-
tudes of 80°, are located inside the polar cap regions, removed poleward from the auroral zones to
minimize anroral interference and geomagnetic cutoffs. These stations include 30 and 50 MHz rio-~
meters, 27 kHz spherics receivers, magnetometers which monitor the horizontal component, and photo-
meters at 3914 & and 5577 3.

Discussion

During its passage across the solar disk, McMath Plage Region 9760 was very inactive, produc-
ing no flares of importance 2 or greater until 18 November. The only visible flare that could be
associated with the energetic proton emission was of importance 1B. It was in progress at 1030 UT,
and located at N21 W87. However, due to the limb position its classification was probably under-
estimated. Type II solar radio emission was observed between 1026 UT and 1105 UT; Type IV was
present between 1026 UT and 1050 UT.

According to the "provisional solar proton event" information in the ESSA Solar-Geophysical
Data Report, No. 292, dated December 1968, the counting rates of the Deep River and Sulphur Mountain
neutron monitors began to increase at 1045 UI, and recorded a maximum inerease of 12% at 1052 UT.
Table I lists the onset times for various physical events.

83



1. INTRODUCTION AND BACKGROUND DATA
by

J. Virginia Lincoln
Space Disturbances Laboratory
ESSA Research Laboratories, Boulder, Colorado

As stated in the foreword, this report has resulted from the several contributions suggested
for study of the cosmic ray ground level event of November 18, 1968, As with other reports in this
series, each person's contribution has been prepared without the benefit of “seeing the others.

This naturally leads to some repetition, but from different viewpoints.

General Activity

The general solar situation on November 18, 1968 is indicated in Fig. 1 which is a reprint of
the solar charts and maps for November 18, 1968 as published in "Solar-Geophysical Data", Number
293, issued January 1969. The most likely flare to associate with this event occurred in McMath
Region 9760. Table 1 presents this region's history in the manner now used in "Solar-Geophysical
Data." The calcium plage data are from McMath-Hulbert Observatory or Catania if in parentheses;
the sunspot magnetic field data from Mt, Wilson Observatory; the area, count and Zllrich classifi-
cation from Sacramento Peak Observatory, or Boulder or Culgoora if in parentheses; and the 9.1 cm
data from Stanford University. The units are explained in "Solar-Geophysical Data Descriptive
Text."

Table 1
McMATH REGION 9760 CMP DATE 11.5 RETURN OF REGION 9736 ROTATION 2
CALCIUM PLAGE DATA SUNSPOT DATA 9.1 CM
Nov.| MC NO. LAT CMD L AREA INT .MWNO.| LAT CMD L MAG 4H AREA CNT C | INT FLUX
4 9760 N18 £88 359 200 1.0 9
5 9760 N19 E83 346 1500 2.0 17045 | N19 E80 346 (Bp) 3 (50) 3 D| 18 WW
6 17045 | N19 E64 346 (Bp) 2 73 12 3 | 14 5
7 (11) (8120) (E55)349 (4503) (4.3) 17045 | N19 E53 346 (By) 3 113 16 D | 16 6
8 9760 N19 E38 348 3000 3.5 17045 | N18 E40 346 (5) 5 (500) 27 D | 24 8
9 (11) (N17) (£26)349 (2847)(3.6) 17045 | N18 E24 346 (6) 5 614 12 H| 28 12
10 9760 N18 Ell 352 3000 3.5 17045 | N19 E14 346 (8) 5 574 9 H/| 38 15
17056 | N17 EOS 355 (Bp) 2
4 9760 N18 WO1 350 3000 4.0 17045 | N19 E02 345 6 563 26 =H - -
17056 | N17 WO7 354 Bp
12 9760 N18 W13 349 3000 3.5 566 34 H| 36 17
13 9760 N17 W26 349 3200 3.5 596 16 H| 34 12
14 (11) (20) (W39)352 (6600) (4.2) (470) 15 c | 30 12
15 (11) (18) (W50) 349 (5653) (5.2) (620) 19 G | 30 10
16 (11) (N20) (W62)348 (5606) (3.4) 17045 | N20 W66 348 6 (450) 14 c }| 26 10
7 17045 | N20 W76 344 (8) 4(450-600) 4 H | 23 9
18 9760 N19 w90 345 1000 3.5 19 9

The final ZUrich relative sunspot numbers, Rz, and the 2800 MHz solar flux, S, associated with
the period are given below; there was no outstanding change on November 18:

Re 8 Re 8

Nov. 16 84 130.5 Noy. 20 92 142.5
Nov. 17 82 143.8 Nov. 21 84 137.1
Nov. 18 77 151.5 Nov. 22 81 134.4
Nov. 19 80 144.8 Nov. 23 76 135.7

Events

For convenience of the user some of the data as published in "Solar~Geophysical Data" are re-
peated here, At the time of the cosmic ray event there was a confirmed grouped flare, number 19246
The flare had two maxima as follows:


[Permission to reprint the following article has been given by the authors and the “Antarctic

Journal of the United States”.]

Investigations of Cosmic Ray
Intensity Variations in Antarctica

Martin A. Pomerantz and Sxaxti P. Duccat

Bartol Research Foundation
of The Franklin Institute

‘The emission by the sun of nuclear particles having
energies as high as several hundred MeV is a rare
occurrence which, on the average, happens only once
every two years, Thus, although the data recorded at
the antarctic cosmic ray stations continue to provide
the basis for a number of unique analytical studies in
which galactic particles serve as probes for investi-
gating the solar-controlled electromagnetic conditions
in interplanetary space, the arrival from the sun of
“newborn” cosmic rays having sufficient energy to
propagate their effects through the earth’s atmosphere
is by far the most spectacular phenomenon that we
can hope to observe with ground-based detectors.
Two such events occurred during 1968: on September
29 and on November 18. The magnitude of the first
was too small to permit extensive analysis (solar-par-
ticle intensity less than one percent above the galactic
cosmic ray background). However, the second was
sufficiently unusual to warrant detailed description
here.

It is interesting to recollect that earlier theories of
propagation precluded the arrival of solar particles at
polar stations, However, cosmic ray flux increases
have been observed during every so-called “ground
level event,” and, in fact, their magnitude has gener-
ally been greater than that at lower-latitude stations
having directions of viewing in the equatorial plane.
Studies of these events have revealed that diffusion
mechanisms play an important role in the transport of
particles from the sun to the earth (Pomerantz and
Duggal, 1961 ; Pomerantz et al., 1961a, b, c; Pomer-
antz and Duggal, 1962; Baird et al., 1967) .

The November 18, 1968 event is the first in which
direct impact of solar particles in the polar regions
has been observed with the new, high counting-rate
neutron monitors. The earlier instruments would not
have provided the high resolution required for the
quantitative analysis that has led to the conclusion
that the dominant mode of propagation in this case
was guidance directly from the sun along magnetic
lines of force. Fig, 1 shows the intensity of solar
cosmic rays as recorded by the Bartol neutron moni-
tors at McMurdo and South Pole Stations, as well as
at the arctic station at Thule, Greenland, and at
Swarthmore, where the particles arrive from the
equatorial plane. Because of its altitude, the South
Pole detector responds to lower-energy particles than
the other stations, hence the magnitude of the in-
crease is enhanced.

The most striking feature is the sharp rise tine, in
marked contrast to the slower-developing previous
events, particularly the last one (January 28, 1967),
described in this journal (Pomerantz, 1968). Max-
imum intensity was attained 15 min after onset, and
the major activity subsided in about 2 hours. This
event occurred while a cosmic ray storm was in pro-
gress, and was associated with a relatively minor (1B)
limb flare at N21° W87° on the solar disk. The
spectrum, deduced from an analysis of data from 18
stations, was of the form k exp(~P/550), where P is
the magnetic rigidity in units of MV.

81

After normalizing the data to remove the effects of
differences in altitude and geomagnetic threshold ri-
gidity, a large variance remains in the magnitude of
the increase as recorded at different stations near the
peak of this event. For example, the percentage in-
crease observed at Thule (76.6°N. 291.6°E.) was
twice that at Alert (82.5°N. 297.7°E.), while no en-
hancement was recorded at the Soviet station at Tiksi
Bay (71.6°N. 128.9°E.).

Ce a a a

8

SOLAR COSMIC RAY INTENSITY, PERCENT
Et

the galactic cosmic
jed the largest flux de-
th's surface

1 googrephic lecation, O is the asympt
16 ofits detector, and the number indicates the

‘cutoff differences) above
the galactic cosmic ray background. The axis of symmetry, +,

ints the position of the apparent source, which is 50°
west of the sun-carth line, corresponding te the garden-hoso
angle charactorizing the Archimedean spiral structure of the

Tingt par

ei

ge

GEOGRAPHIC LATITUD!
2

gis 3 38

W018 59905308 30 40 G0 Te0 TBO ito
GEOGRAPHIC LONGITUDE

In Fig. 2, the normalized maximum percentage in-
creases during a 20-min interval are indicated in cir-
cles representing the approximate asymptotic direc-
tions of arrival of the solar particles to which the
detectors at the specified locations (X) respond. Our
analysis reveals that the intensity increase was symme-
tric with respect to a point on the celestial sphere with
geographic coordinates 20°S. 40°W. This location
was 50° west of the position of the sun at that time,
which conforms with the Archimedean spiral struc-
ture of the interplanetary magnetic field and confirms
that the solar particles were magnetically guided from
the source. Because of the rapid decrease in the flux
to a low level shortly after the maximum, it is not
possible to determine when diffusion ultimately
became the principal propagation mechanism.



"Geomagnetic Disturbances During the Period November 16-21, 1968
Associated with the McMath Plage Regions 9760, 9772 and 9780"

by

K. Kawasaki and 8.-I. Akasofu
Geophysical Institute, University of Alaska
College, Alaska 99701

ABSTRACT

A compilation of magnetograms of. selected observatories for the period November
16-21, 1968 is presented. The period covered includes a large Forbush decrease in
cosmic rays which began during November 16, 1968 and the intense cosmic ray increase
of November 18, 1968. The Forbush decrease and the geomagnetic storm of November
16/18, 1968 were probably associated with the McMath plage region 9772 and the solar

cosmic ray increase and the weak geomagnetic storm of November 20/21, 1968 with the
plage region 9760.

Major si are identified for this moderately disturbed period.

Magnetograms compiled from observatories widely dispersed in longitude show that the period
November 16-21, 1968 was only moderately disturbed. A moderate Forbush decrease and a solar pro-
ton event were also observed during this period [Venkatarangan, et al., 1969; "Solar-Geophysical
Data", January 1969]. It is of interest to study in detail the geomagnetic disturbances and to
identify the probable regions producing the enhanced geomagnetic activity.

Table 1 is a summary of the geomagnetic activity in terms of the three-hourly Kp indices and
sum of Kp during the period. The indices for the three days prior to November 16 are also tabu-
ated and show only minor activity was recorded on November 14 and 15, both being designated as
International Quiet Days.

Table 1

1968 THREE HOURLY KP INDI KP_SUM
November 13 oF 1- 1 2 i+ + 2+ 2+ un
November 14 OF oF 1- oF 1 1 2- 2 ad
November 15 ae a+ 1 1- 0 OF OF 5
November 16 i+ 1 1- 30 Se ae ae ce 22-
November 17 we 2 4- 2 3 4 ot 4- 26
November 18 5-0 S= 4 4-0 t 3 co cas 27+
Wovember 19 2+ 2 2- 2 2 to 1- 12+
November 20 vis 1 1 ae Se 4 co 2- 21-
November 21 2- 1 1- 1- 2 a 3 12+

table 2 is a list of 27 flares numbered consecutively which occurred during the period Novem-
ber 13-21, 1968 and which were reported to be of Importance 2 1 by at least one observatory. ‘The
flares of the three days prior to November 16 are included to allow for the transit time between

the beginning of a flare and the subsequent arrival of flare particles at the orbit of the earth.

There were only four major regions of flare activity - McMath plage regions 9760, 9768, 9772
and 9780, which will be designated as M9760, M9768, M9772 and M9780, M9768 produced only one of
the 27 flares. M9760 was first observed on the eastern limb of the sun on November 4 and passed
out of the field of view on the western limb on November 18. M9772 appeared on the eastern limb
on November 13; it did not pass out of view during the interval studied. M9780 was first noted
near the eastern limb on November 19,

92



Table 3 (Continued)

LINDAU 51e60N 10610E GERMANY
NEUTRON MONITOR 18-NM-64

TEN-MINUTE BAROMETER CORRECTED RATES / 100

NOVEMBER 18s 1968

TIME MINUTES AT END OF INTERVAL
Usle 10 20 30 40 50 60
900-1000 572 571 578 573 573 573
1000-1100 571 574 577 572 575 579
1100-1200 577 576 575 577 578 577
1200-1300 573 575 576 577 575 575
1300-1400 574 577 572 578 574 576
CLIMAX 39037N 253682E COLORADO

IGY NEUTRON MONITOR
FIFTEEN-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 18% 1968

TIME MINUTES AT END OF INTERVAL
Uele 15 30 45 60
700- 800 889 908 900
800~ 900 902 901 899 902
900-1000 915 904 896 894
1000-1100 907 915 911 949
1100-1200 913 914 917 910
1200-1300 916 910 918 916
1300-1400 913 913 914 914
1400-1500 913 909 912 911
1500-1600 912 917 912 910
1600-1700 917 iY) ie) 0
1700-1800 i) 0 903 901
1800-1900 907 910 911 913
1900-2000 899 898 902

DALLAS. 32e78N 96.80W TEXAS

NEUTRON MONITOR NM~64

BAROMETER REFERENCE 995 MILLIBARS
ATTENUATION COEFFICIENT 13762 MILLIBARS
REAL COUNTS 40 TIMES TABULATED COUNTS
FIVE-MINUTE HOURLY RATES

NOVEMBER 185 1968

TIME MINUTES AT END OF INTERVAL
Usle 05 10 15 20 25 30 35 40 45 50 55 60 AVERAGE

900-1000 1437 1452 1438 1440 1456 1439 1441 1440 1426 1441 1428 1442 1440
1000-1100 1435 1439 1415 1434 1443 1433 1435 1453 1452 1464 1462 1440 1442
1100-1200 1459 1429 1442 1451 1441 1439 1436 1438 1443 1444 1432 1452 1442
1200-1300 1451 1452 1435 1451 1436 1449 1437 1455 1440 1433 1436 1449 1444
1300-1400 1433 1450 1434 1453 1433 1441 1450 1446 1439 1450 1452 1460 1445
1400~1500 1460 1433 1440 1447 1444 1446 1447 1450 1445 1442 1433 1436 1443

60



15

205
203
206
203
205
206
200
201
202
205
202
223
213
213
2i1
212
212
210
208
207
203
201
203
200

Table 3 (Continued)

MINUTES AT END

20

205
205
205
199
203
203
205
203
204
202
208
218
213
210
210
212
209
208
211
207
209
206
206
201

IN MILLIBARS

RIGHT UNIT
TIME
UsTe 05 «10
000- 100 205 205
lo0~ 200 205 207
200- 300 203 209
300- 400 206 200
400- 500 203 203
500- 600 204 201
600- 700 206 204
700- 800 201 203
800- 900 201 202
900-1000 202 201
1000~1100 204 202
1100-1200 226 225
1200-1300 214 208
1300-1400 213 207
1400-1500 212 «214
1500-1600 211 210
1600-1700 210 211
1700-1800 213 210
1800-1900 206 209
1900-2000 208 206
2000-2100 209 208
2100-2200 203 201
2200-2300 205 205
2300-2400 203 201
PRESSURE
TIME
UsTe 05 «10
000- 100 7654 7655
100- 200 7656 7656
200- 300 7656 7656
300- 400 7662 7662
400- 500 7660 7661
500- 600 7664 7664
600- 700 7665 7665
700- 800 7664 7663
800~ 900 7662 7663
900-1000 7659 7660
1000-1100 7657 7658
1100-1200 7654 7653
1200-1300 7654 7655
1300-1400 7651 7651
1400-1500 7652 7651
1500-1600 7650 7649
1600-1700 7648 7648
1700-1800 7641 7643
1800-1900 7650 7650
1900-2000 7652 7652
2000-2100 7658 7658
2100-2200 7667 7666
2200-2300 7673 7675
2300-2400 7680 7682

15

7656
7657
7656
7663
7660
7665
7666
7663
7662
7661
7659
7652
7653
7651
7652
7650
1647
T7644
7651
7652
7657
7666
7676
7681

25

205
204
205
203
204
204
201
204
204
206
204
215
210
210
206
213
210
211
209
208
208
206
205
201

30

205
202
206
206
203
200
203
203
202
201
203
216
211
212
209
210
210
211
206
205
205
203
204
204

MINUTES AT END

20

7657
T7657
7657
7663
7661
1663
7664
7662
7662
7661
7658
7654
7654
7651
7650
7651
7647
7646
7654
7653
7657
7667
7674
7682

25

7657
1658
7658
7662
7660
7663
7665
7662
7662
7660
7657
7654
7654
7651
7651
7651
7648
7646
1654
7656
7657
1667
7674
7684

56

30

7658
7658
7659
7663
7661
7663
7665
7662
7662
7661
7657
7653
7654
7649
T7649
7651
7646
7647
7656
7657
7660
7668
7676
7683

OF INTERVAL

35

206
201
203
204
203
202
202
204
202
201
205
220
211
211
212
212
213
208
204
209
204
204
204
204

40

208
203
207

201.

201
204
203
204
203
205
205
214
214
214
211
209
212
208
207
205
205
203
205
204

45

202
204
206
203
207
200
201
200
203
200
203
215
213
209
210
213
211
212
211
207
203
205
204
204

OF INTERVAL

35

7658
7657
7659
7663
7663
7664
7665
7662
7662
7660
7657
7654
7652
7650
7650
7650
7646
7645
7653
7657
7661
7666
7677
7684

40

7657
7656
7660
1662
7664
7665
7664
7662
7660
7660
7657
7655
7652
7650
7649
7649
7645
T1647
7653
7655
7660
7664
7678
7684

45

7656
7656
7660
7662
7665
7664
7664
7661
7661
7659
7655
7654
7652
7651
7649
1649
7646
7648
7654
7657
7659
1663
7679
7685

50

203
205
204
203
203
205
202
203
202
204
217
212
209
210
209
208
209
209
211
206
203
207
200
205

50

7658
7657
7661
7661
7664
7663
7664
7661
7661
7659
7653
7654
7652
7651
7648
7649
7647
7649
7655
7657
7663
7666
7678
7686

55

202
207
202
207
202
206
203
206
204
203
244
213
212
208
211
212
211
209
205
207
206
206
206
201

55

7657
7657
7661
7660
7664
7664
7664
7661
7661
7659
7654
T7654
7651
7651
7650
7648
T7644
7648
7654
7658
7665
71669
7679
7686

60

204
203
201
203
201
204
207
203
203
206
240
214
213
211
212
207
205
206
207
206
203
203
201
201

60

7657
7657
1662
7661
7664
7665
7664
7661
7660
7657
7655
7654
7651
7652
7649
7648
7645
7649
7653
7659
7665
7672
7678
7687



TABLE 2, Temperatures and Densities of Limb Bursts at 36 GHz

Flux Units,
‘MeMath ESSA 10-2! W/m? He
Dato Plage No. Flare No. ‘Temperature, *K at 36 GHz Atea*
Aprit 1, 1907 8740 4mm) 1.2 X 108 4000 320
July 6, 1968 9503 16373 3.9 X 108 24000 220
Nov. 18, 1968 9760 0.7 X 10 6500 310
Mean 2 X10

+ Optically observed area (maximum) in 10-¢ of the solar disk,

5. Inverrrerarion

‘The fact that the abnormal bursts at the limb
originate from regular plage regions indicates
that these bursts are normal ones. It remains
to be explained why flares observed in profile
present higher intensities than flares facing the
observer. If it is -assumed that the gaseous
envelope rises ahead of the flare and becomes
more tentious with distance from the base of
the flare, we have to consider the radiation of
a thin layer at different points on the solar
disk, namely cos § = 0 to 1, where 8 is the
angle between the normal and the line of sight
to the observer, The contribution of a thin
layer with optical thickness dz at the optical
depth + is given by Unséld [1955]

J = constant o'"*! dr see 8

3)

Normalized to unity at § = 0 this function
shown in Figure 7 gives the contribution of the
intensity of a thin layer versus the distance
from the center of the sun expressed in terms
of cos 8. For layers 7 < 0,001 it is seen that
the intensity at the limb is at least 100 times
greater than at the center. Thus we receive at
millimeter wavelengths the full brightness of
the sporadic condensation shell at the limb.
Owing to the fact that the optical thickness
depends on the wavelength, the lower curves
represent the situation at centimeter wave-
lengths and longer.

‘The experimental observations indicate that
limb bursts exhibit, if at all, only. weak post-
burst components [Feiz, 1969]. If the apparent
center of the burst activity is slightly behind
the solar limb, it is interesting that the burst is
only impulsive. This suggests that the source
of post-burst radiation is situated at layers
around 10,000 km. We find a similar situation
for the slowly varying component, ie. the radia-
tion of a plage at millimeter wavelengths. In
Figure 7 the average vahtes P of the relatively
strong plage $742 are graphed. According to the
flat Jayer model, + must be between 1 and 2.
The darkening of a plage near the Jimb was
investigated in many eases and seems to be a
common feature. These and other’ data [Nagui-
beda, 1967} point to a flat sonree of consider-
able optical thickness. The MM-burst data sug-
gest a similar model for the post-burst compo-
nent as well.

18

whe

Zig. 7. Normalized contribution of a thin layer
versus cos 3; P, daily average valucs of the
millimeter intensity of MeMath plage no, 8818.

6. Conciusion

‘The radio burst at millimeter wavelengths is
believed to be produced by two components:
(1) By a component originating from an opti-
cally thick Jayer located at the height of the
flare hase. This component is responsible for
the gradual rise and fall as well as for the pos
inerease phase of a burst. Estimated temper:
tures after the impulsive component may be in
the range 30,000°K to $0,000°K, (2) By an
impulsive component due to an optically thin
shock front of the mean temperature 2 x 10°°K
rising ahead of the chromosphere into the
corona,

‘REFERENCES

Feix, G.. MM-Burst_ observations by a_peneil
beam-research note, Solar Phys, (in press), 1969.
Nagnibeda, V. G., Properties of sources of the
slowly varying component of 2 cm solar radio

Unsild, A, Physik der Steraatmosphéren, p, 113,
Springer-Verlag, Berlin, 1955.



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Table 3 (Continued)

GOOSE BAY 53.16N 60024W CANADA
NEUTRON MONITOR 18-NM~64

REAL COUNTS 100 TIMES TABULATED COUNTS
FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES
NOVEMBER 18+ 1968

TIME MINUTES AT END OF INTERVAL
Uels 05 10 15 20 25 30 35 40 45

900-1000 6216 6216 6193 6123 6199 6152 6187 6175 6082
1000-1100 6100 6140 6170 6182 6140 6211 6187 6129 6211
1100-1200 6643 6597 6451 6433 6369 6427 6369 6340 6399
1200-1300 6264 6310 6345 6240 6310 6322 6369 6317 6258
1300-1400 6211 6188 6270 6129 6211 6223 6235 6281 6310
1400-1500 6228 6264 6264 6240 6292 6269 6252 6217 6164
1500-1600 6204 6263 6134 6204 6234 6228 6228 6228 6187
1600-1700 6198 6187 6245 6268 6268 6268 6257 6198 6169
1700-1800 6216 6263 6239 6234 6222 6199 6246 6275 6252
1800-1900 6188 6223 6153 6182 6217 6241 6182 6165 6206
1900-2000 6300 6218 6206 6241 6230 6171 6247 6236 6212
2000-2100 6242 6189 6177 6242 6349 6148 6266 6225 6160
2100-2200 6249 6225 6149 6220 6220 6250 6232 6267 6214
2200-2300 6232 6196 6232 6232 6220 6268 6291 6191 6202
2300-2400 6220 6262 6215 6215 6304 6221 6221 6269 6257

OULU 65e00N 25042E FINLAND
NEUTRON MONITOR 9~NM-64
FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 18» 1968

TIME MINUTES AT END OF INTERVAL
Usle 05 10 15 20 25 30 35 40 45

800~ 900 278 #273 276 274 278 280 283 283 276
900-1000 277 278 280 276 276 278 272 273 276
1000~1100 279 282 283 276 280 282 281 277 280
1100-1200 278 276 282 284 283 283 279 284 280
1200-1300 281 276 278 284 283 278 281 281 276
1300-1400 282 286 280 280 286 286 279 280 276
1400-1500 278 283 280 283 281 284 285 282 281
1500-1600 281 286 277 277 #283 276 277 282 278
1600-1700 280 276 284 282 284 279 284 276 276
1700-1800 282 285 280 280 278 285 283 284 284
1800-1900 285 278 279 278 279 280 283 288 282

51

6199
6433
6375
6293
6193
6211
6181
6204
6193
6230
6277
6237
6261
6208
6191

50

276
281
280
283
287
282
285
280
276
284
284

55

6129
7064
6334
6270
6258
6152
6216
6204
6299
6300
6277
6249
6250
6226
6167

55

283
278
282
277
281
278
282
276
286
283
281

6175
6866
6357
6317
6264
6111
6198
6251
6223
6165
6242
6202
6261
6262
6209

60

275
281
276
278
280
277
276
285
279
278
282

60 AVERAGE

6170
6319
6424
6301
6231
6222
6209
6226
6238
6204
6238
6224
6233
6230
6229



Rigidity

(cv)

20,00
15.00
10.00
9.00
8.00
7.00
6.00
5.00
4,90
4.80
4.70
469
468

FE

SEEPRE SERS OED DOD eae

BS EGETISSSANGEUAVGOSLNG

PPP PPP PPP PPP Pere epee

Geographic Latitude
Geographic Longitude
UT = 1100
Geomagnetic Time = 0450

DALLAS, U.S.A.

32.78 N
96.80 Ww

LT = 0433
Asymptotic
Lat Long
-6.77 -51,06
-20.71 ~43,.25
-31.12 ~ 27,06
-30.03  --22.15
-27 4 15.73
-23.63 ~4,97
715.53 17.40
27.20 7h AS
32.13 94.06
25.21 123.39
718.73 178.86
-9.76 = 200.43

3.94 246. 7H
-10.82 219.19
-26.80 295.90

-5.36 314.25
-9.14 394.14
~13.25 229.72
7.13 146.95
73.35 145.73
-3.82 180.28
-11.45 250.77
~12.36 243 14
-1.19 146.56
8.56 222.78
17.74 195.69

2.02 168.00

19.39 190.72

13.53 207.92

4,96 151.79

R R

R R

R R

R R

R R

R R

R R
20.36 168,49
13.02 95.25

PREPPPFPFPFPFF

BULL UL UR RR RRR RANRWWHWOUY

SSERREVRSSS=ANG FART HOSLSGEGAVHGSAHGERH

2 0eco00OL-~~

PPPRREE PEPPER PEPPERS SE

Asymptotic
lat Long
17.9% 172.53

2.76 204, 24
-7.18 234.48
12.93 194.93
12.41 186.34

R R

1.55 228 41

R R
+9616 224.81
15.04 175.63
~6 KT 243.78

R R
~6.70 247.03
425 213.42
7.08 56.27

R R

R R
6.53 132.05

R R

R R
11.01 186,28

-12.01 224,01
“456 217.95
“8.42 320.32

R R

R R

R R

R R

R R

~18,08 321.69

R R

R R

R R
18.17 103.31

R R

R R

R R

R R

R R

- 3.85 all reentrant trajectories



“Data Concerning November 18, 1968, in Addenda to ‘Solar Circumstances
at the Cosmic Ray Decrease on January 28, 1967'"

by

Helen W. Dodson and E. Ruth Hedeman
McMath-Hulbert Observatory, The University of Michigan

[Permission has been given by the authors and the publisher to reprint portions
of the article appearing in Solar Physics, 9, 278-295.]

The following paragraphs and figures are from the Addenda of the article.

In recent months two additional, well defined enhancements of cosmic rays have been
detected by ground-based equipment: 1968, November 18 and 1969, February 25,
According to information currently available to us consideration of solar circumstances
associated with these new events docs not modify evaluations expressed in the body
of this paper.

On November 18, 1968 the cosmic ray enhancement was in appropriate time associ-
ation with a flare at the west limb for which initial reports indicate importance | in Hz.
Accompanying ionospheric and radio frequency phenomena suggest that the, flare
was a major solar event. Preliminary data show that this cosmic ray flare occurred
in a region that had been only moderately flare-rich in its transit across the solar disk
even though the plage contained a y-5 type spot with maximum area ~800 millionths
of the hemisphere. Three days prior to the cosmic ray flare of the 18th, spot area had
diminished markedly té ~200 millionths. When the region reappeared at. the east
limb in December, it had declined in activity. The Spot area was still ~200 millionths
of the hemisphere and the plage was of only average size and brightness. The only
known major event in the region in December was a flare of importance 3 at the east
limb on December 2. Polar Cap Absorption followed this flare. The flare on December
2 apparently was another case of an ‘isolated’ major flare in the late and declining
phase of a region associated with energetic cosmic rays (see Figure 2).

oar oF
‘COSHIE RAY
FLARE

1942 Fan.

1945 uy 28
1949 Wop 19
1956 Fen23

1956 Avg 3s

1959 ly 16

1960 Moy 4 22

1960 Sept
1960 Wor. 12,15, 20
1961 ty 18,20
1966 wy 7

1967 Jon 28

Fi Schematic presentation of information relating to all known regions in which energetic
cosmic ray flares occurred, 1942-1968, The slender rectangles represent passage across the solar disk
of regions in which energetic cosmic ray flares occurred. Dashes indicate transit of the invisible
hemisphere. The days on which energetic cosmic ray flares occurred are shown by black squarcs.
‘Numerals 2 and 3 indicate the importance and approximate time of ‘isolated major flares’ in subse-
quent rotations, Data more than one rotation prior to cosmic ray flares have been omitted,

The foregoing ground-level enhancements of energetic cosmic rays in 1968 and
1969, coming as they do near the probable time of maximum in the solar cycle,
constitute departures from the pattern of solar cycles 18 and 19 in which such increases
were not observed during the years of solar maximum, The detection of energetic
cosmic ray increases in 1968 and 1969 may be a further indication that solar-terrestrial
circumstances in the present solar cycle are somewhat different from those that pre-
vailed during the two preceding cycles.



TIME
UsTe

TIME
UsTe

000-
100-
200-
300-
400-
500-
600~-
700-
800-

SULPHUR MOUNTAIN

Table 3 (Continued)

NEUTRON MONITOR NM-64
FIVE-MINUTE UNCORRECTED AND PRESSURE HOURLY RATES

NOVEMBER 185 1968

05 10 15

LEFT UNIT

05 10 15

100 203 204 200
200 205 203 204
300 203° 204 202
400 205 203 201
500 196 205 202
600 203 200 203
700 201 200 201
800 201 198 201
900 203 201 201

900~1000 202 200 199
1000-1100 205 201 204
1100-1200 225 221 216
1200-1300 209 212 207
1300-1400 211 208 213
1400-1500 206 208 209
1500-1600 210 210 212
1600-1700 209 210 209
1700-1800 208 210 207
1800-1900 208 205 205
1900-2000 208 205 204
2000-2100 204 209 202
2100-2200 202 201 200
2200-2300 203 202 203
2300-2400 205 198 203

TIME
Ueleo

000~
1oo-
200~
300-
400~-
500-
600-
700-
800-

CENTER UNIT

05 10 15

100 225 227 226
200 228 229 226
300 232 231 226
400 229 231 226
500 227 229 226
600 228 224 227
700 224 225 225
800 226 225 225
900 224 229 224

900-1000 223° 225 226
1000-1100 227 #228 225
1100-1200 256 249 248
1200-1300 236 236 236
1300-1400 224 236 234
1400-1500 232 236 234
1500-1600 236 231 233
1600-1700 233° 234 233
1700-1800 238 235 231
1800-1900 234 231 232
1900-2000 229 230 233
2000-2100 231 233 230
2100-2200 226 226 226
2200-2300 227 227 223
2300-2400 230 222 225

51+20N 115.60W

CANADA

MINUTES AT END OF INTERVAL

20

MINUTES AT END

20

203
199
206
203
201
201
204
199
207
205
200
218
214
208
209
215
208
211
207
205
207
202

200
198

MINUTES AT END

20

226
226
228
229
225
224
229
226
227
226
230
242
235
236
234
236
236
231
234
226
230
230
227
223

25

25

205
207
202
205
204
199
200
205
202
202
202
217
212
213
213
212
208
206
205
208
208
203
202
202

25

229
227
226
226
227
225
227
225
226
229
227
239
233
236
235
234
231
234
228
232
229
228
230
226

55

30

30

206
204
202
201
206
202
204
203
206
204
203
217
210
209
207
210
205
207
208
207
203
203
203
201

30

228
227
229
225
228
228
224
224
227
226
228
240
240
237
230
232
230
235
230
230
233
227
228
225

35

OF IN
5

204
204
201
201
202
205
201
201
203
205
203
211
210
210
207
209
211
208
207
208
205
205
205
204

40 45

TERVAL

40 45

203 203
205 203
201 202
207 203
200 201
200 202
201 199
200 204
201 202
201 200
204 204
213° 214
211 210
208 208
210 212
206 205
206 206
209 207
204 208
204 206
208 209
201 204
200 204
200 203

OF INTERVAL

35

227
228
228
226
227
226
227
223
226
228
226
241
235
237
235
235
232
231
229
231
226
227
230
221

40

227
227
224
225
227
226
228
229
224
226
228
240
235
233
236
232
234
231
233
228
229
224
228
226

45

227
225
229
224
226
227
226
225
225
229
224
237
237
236
238
234
233
234
235
228
226
226
224
224

50

50

199
206
203
202
204
202
201
202
203
204
214
212
209
208
209
211i
209
204
205
206
207
206
204
199

50

226
227
229
223
226
224
227
226
222
225
238
239
236
237
236
232
235
234
229
233
227
226
224
229

55

55

199
204
202
204
203
204
203
201
201
200
242
213
209
208
208
211
208
209
206
207
203
204
202
200

55

224
228
227
226
221
230
226
225
232
222
268
239
237
234
239
236
232
237
230
229
229
229
226
221

60

60

206
203
205
206
201
204
202
204
204
202
239
215
212
209
210
208
208
209
208
207
205
204
204
197

60

230
229
225
233
225
226
229
227
228
228
264
238
237
238
230
237
232
231
229
226
227
227
226
230



TABLE OF CONTENTS

Page

FOREWORD
A. H. Shapley 1
1, INTRODUCTION AND BACKGROUND DATA 5

J. Virginia Lincoln

2. SOLAR REGION
“Preceding Changes in the Active Region" 9
(Constance Sawyer and Sara F. Smith)
"Data Concerning November 18, 1968, in Addenda to 'Solar Circumstances at
the Cosmic Ray Decrease on January 28, 1967'" 13
(Helen W. Dodson and E. Ruth Hedeman)

3. SOLAR RADIO EVENTS

"On the Type IV Burst of November 18, 1968" 14
(A. Kruger)

"An Outstanding mm-Radioburst Observed November 18, 1968” 7
(G. Feix)

"The Radio Outburst of November 18, 1968 at 1026 UT Observed at Metric Waves

with High Temporal Resolution" 20
(A. Abrami)
4. SOLAR X-RAYS

"Solar X-Ray Emission on November 18, 1968" 23
(D. M. Horan and R. W. Kreplin)

"Solar Cosmic-Ray Event on 18 November 1968" 26

(Stephen Pinter)

5. SPACE OBSERVATIONS
"Editorial Comments" 30
(5. Virginia Lincoln)
“Explorer 34 Solar Proton Monitoring Experiment, Ep >10 Mev, November 17 -
28, 1968" 31
(C. 0. Bostrom, D. J. Williams and J. F. Arens)
“Bnergetic Proton Flux (5-70 Mev) at Synchronous Orbit November 11 -
December 8, 1968" 32
(G. A. Paulikas)
"Protons, Alpha Particles, and Electrons Resulting from the 18 November 1968
Solar Flare" 34
(. J. Lanzerotti)
"Pioneer 9 Solar Wind Velocity and Electric Field Data 8 November 1968 to
4 January 1969" 40
(ira M. Green and F, L. Scarf)

6. COSMIC RAYS
“Tabulations and Selected Graphs of Neutron Monitor Observations November 18,

1968" 43
(J. Virginia Lincoln)
"Scintillation Monitor Bologna, Italy 15-minute Observations" 64
(M. Galli)
"Events of November 15 to November 22, 1968" 66

(John F, Steljes)
“Asymptotic Directions of Approach Appropriate for the High Energy Solar

Proton Event of November 18, 1968" 68
Qf. A. Shea and D. F. Swart)
"Investigations of Cosmic Ray Intensity Variations in Antarctica" 81

(Mi. A. Pomerantz and S. P. Duggal)



WILKES, ANTARCTICA

Geographic Latitude ~- 66.42 $
Geographic Longitude - 110.45 E
UT = 1100 LT = 1822
Geomagnetic Time = 1733

Rigidity Asymptotic
(ev) LAT LONG
20.00 -59.00 105.31
15.00 -59.83 103.25
10,00 107.12
5.00 107.95
4.00 109.87
3.00 111,12
2.00 111.35
1,00 119.99
0.90 121.88
HEISS ISLAND, USSR
Geographic Latitude - 80.33 N
Geographic Longitude - 57.80 &
UT = 100 LT = 1451
Geomagnetic Time = 1617
Rigidity Asymptotic
LAT LONG
20.00 70.83 95.99
15,00 68.78 94.20
10.00 67.41 94.48
5.00 61.58 97.63
4,00 59.95 101.01
3.00 57.77 101.76
2.00 53.34 106.06
1,00 45598 115.63
0.90 4h.40 117.54

INUVIK, CANADA
Geographic Latitude - 68.35 N
Geographic Longitude - 133.73 W
UT = 1100 LT = 0205
Geomagnetic Time = 0055

Rigidity Asymptotic

(cv) LAT LONG
20.00 47,03 -119.94
15.00 42.64 -123.30
10,00 38.84 125.98
5.00 24,28 -127.63
iL00 19.37 -127.20
3.00 9.71 -132.26
2,00 “4.94 -143.20
1,00 -12.06 -187.94
0.90 -7.97 197.91

72

MIRNY, ANTARCTICA

Geographic Latitude - 66.55 $
Geographic Longitude - 93,00 £
UT = 1100 LT = 1712
Geomagnetic Time = 1514

Rigidity Asymptotic
(gv) LAT LONG
20,00 “51.11 84.73
15.00 “51.24 79.94
10,00 4 80.35
5.00 80.24
4,00 83.92
3.00 82.38
2,00 82.98
1,00 86.19
0.90 87.13
SOUTH POLE, ANTARCTICA
Geographic Latitude - 89.98 S$
Geographic Longitude - 0,00 E
UT = 1100 LT = 1100
Geomagnetic Time = 0718
Rigidity Asymptotic
(cv) LAT LONG
20.00 -63,.08 = 5.72
15.00 58.69 6.03
10.00 -58.26 -19.50
5.00 -50.04 -18.60
4,00 -50.47 -17.89
3.00 -4h.37  -20.26
2.00 -37.84 ~-17.60
1,00 -20.80 -16,36
0.90 -17.84 15.59

CHURCHILL, CANADA

Geographic Latitude - 58.75 N
Geographic Longitude - 94,09 Ww
UT = 1100 LT = Ob4y

Geomagnetic Time = 0450

Rigidity Asymptotic
(ev) LAT LONG
20.00 4I11 -71.61
15.00 35.94 -72.97
10.00 31.21 -75.70
5.00 19.66 -73.93
4,00 16.58 ~72.80
3.00 9.89 -72.46
2.00 -0.21 -69.46
1,00 -20.92 -61.80
0.90 -24.32  -59.73



27


SHEA,
D. F.
K. G.

SHEA,
DF.
K. G
U. Re

M. A, 1965
SMART, and
McCRACKEN

MAL, 1968
SMART,

McCRACKEN, and

RAO

WILLIAMS, D. J., and 1965

GD

MEAD

A Study of Vertical Cutoff Rigidities Using Sixth
Degree Simulations of the Geomagnetic Field, J, Geox

phys. Res., 70, 4117.

Supplement to IQSY Instruction Manual 10, Cosmic-Ray
Tables, Special Report No. 71, AFCRL 68-0030.

Nightside Magnetosphere Configuration as Obtained
from Trapped Electrons at 1100 Kilometers, J. Geo~
ys. Res., 70, 3017.

70



NGVEMBER 18 1968 CORRECTED NEUTRON: MONITOR

F

1co-Fie q ‘i yin, palin acetyl
100 Aer LL Mae {ul ath flew, PAY Pu
IM
co wgll {tan tg oe
100-lalb pred! "ie ane ala 1 Myra lle Minn
ni vp iT yi ypu

GOOSE
BAY

DEEP
RIVER

INUVIK

ALERT

3g 1
GORDI

Fig. 3.

oO 11 12 13 14 15 16 17 18 19 20 21 22 23 2
NATE SCOLE S.Q PERCENT

5-minute data from Goose Bay, Deep River, Inuvik and Alert
0900-2400 UT November 18, 1968.

63

4



"The Radio Outburst of November 18, 1968 at 1026 UT
Observed at Metric Waves with High Temporal Resolution"

by

A. Abrami
Astronomical Observatory, Trieste, Italy

The radio outburst occurred at 1026 UT on November 18, 1968 and was associated with the second-
ary maximum of an optical flare of importance 1b, which started at 1026 UT at position N20 W90. It
has been observed at the Trieste Astronomical Observatory with the metric waves radiometer (239
Miz) and the high temporal resolution recording equipment already described in a preceding report
of this series [ABRAMT, 1970].

qhe time profile of the event is presented here in two separate diagrams ranging from oh26"0s
to 10°29TM6§ and from 10h29"0$ to 10432m36S UT (Figure 1) obtained from the original records by
means of the same reduction technique already quoted [loc. cit,]. These diagrams represent the
initial more variable phase of the phenomenon. Its whole evolution is sketched in the diagram of
Figure 2 obtained from the measures of the enhanced background made at low resolution. In this fi-
gure the part of the diagram observed at high resolution is underlined.

The more relevant data obtained from these profiles are as follows:

Starting time earlier than 1026375 UT
Time of the first maximum loh26masss 8s
Time of the second maximum 1oh29M45S+ 15
Time of the third maximum 1ohgims4s+ 55
Duration about 39m
Peak flux density greater than 1600 x 107?*wm-*H274
Total energy emitted

until 10432m36S greater than 15 x 10728 gm7?H2-*

REFERENCE
ABRAMI, A. 1970 Some radio bursts in the period October 29 - November

3, 1968 observed at metric waves with high temporal
resolution. World Data Center A ~ Upper Atmosphere

Geophysics Report UAG-8, ESSA, Boulder, Colorado,
163-168.

20



Electron Observations

The electron counting rates measured in three energy channels are plotted in Figure 4. The
background counts in each channel are equal to the rates measured during November 17, After sub-
tracting the backgrounds the integral electron fluxes in terms of electrons (cn sec ster)~' can
be obtained approximately by multiplying the Hl rates by 57, the H2 rates by 7.2, and the H3 rates
by 7.2.

The electron rate onset times on November 18 were energy independent and approximately equal
to the proton and alpha particle onset times. The initial sharp enhancement after the electron
onsets was seen in all of the electron channels. The electron decay times beginning on November
21 were approximately energy independent and nearly equal to the proton and alpha decay times.

Energetic Storm Particles

The four lowest energy proton channels and the lowest energy alpha particle channel all show
approximately steady increases of the particle fluxes up to the time of the sudden commencement
(Figures 1 and 2), In particular, the two lowest energy proton channels show flux peaks of sev-
eral hours duration around the time of the sudden commencement. These energetic storm particle
enhancements have often been discussed previously [Axford and Reid, 1963; Rao et al., 1967].

DAY, 1968, UT
322 323 324 325 326 327

1075
C sc q
we an Hi 4
10 E>300 keV ~J
x FL q
fe) awe
10° E- aneas-|
© pew =
2 - 7 oO
2 = 107 $
z C pe mene «| H2 q 3
rat L E>500 kev 4 1 -
° L- | 10 Ss
E 4 ro
é L ieee ee
5 L— -410° 3
Cc q a
Fi rev dist 8
2 10
10 E 4 a
10' perm H3
cn aw E>tMeV
0° ane
ey

17 18 19 20 24 22
NOVEMBER, 1968, UT

Fig. 4. Electron counting rates measured following the 18 November 1968 solar flare.
37



PORT AUX FRANCAIS

Table 3 (Continued)

490358

NEUTRON MONITOR 18-NM-64

70«25E

CORRECTED FOR BAROMETRIC PRESSURE

COEFFICIENT

MULTIPLY INDICATED NUMBERS BY 400

FIFTEEN-MINUTE HOURLY RATES

MINUTES AT END

20 25

1444 1429
1431 1445
1466 1448
1465 1456
1441 1438

44630N

30

1439
1421
1448
1454
1447

1061 PER CENT PER CM HG

KERGUELEN IS.

OF INTERVAL

35

1423
1433
1455
1467
1448

288670E

FIVE-MINUTE BAROMETER CORRECTED RATES

NOVEMBER 185 1968
TIME
Uele 05 lo 15
900-1000 1429 1427 1429
1000-1100 1439 1445 1437
1100-1200 1461 1473 1447
1200-1300 1454 1474 1429
1300-1400 1456 1445 1432
MT WASHINGTON
IGY NEUTRON MONITOR
NOVEMBER 18» 1968
MONITOR A
TIME
Usle 05 lo 15
900~1000 8596 8273 8793
1000-1100 8734 8305 8528
1100-1200 9290 9162 8997
1200-1300 8804 9094 9128
1300-1400 8797 8580 8844
MONITOR B
TIME
Uele 05 lo 15
900-1000 8273 8199 8321
1000-1100 8263 8454 8180
1100-1200 9015 8938 8847
1200-1300 8380 8571 8530
1300-1400 8599 8406 8349

MINUTES AT END

20 25

8544 8531
8380 8502
8634 9127
8788 8641
8437 8592

30

8435
8831
8836
8727
8628

MINUTES AT END

20 25

8395 8232
7909 8205
8684 8555
8489 8516
8264 8543

57

30

8261
8261
8662
8677
8431

OF IN
35

8555
8399
8992
8680
8714

40

1403
1436
1443
1451
1456

45

1427
1431
1457
1463
1442

50

1424
1444
1447
1452
1444

NEW HAMPSHIRE

TERVAL

40

8435
8596
8863
9178
8709

45

8709
8484
8965
8806
8779

OF INTERVAL

35

8257
8299
8494
8655
8442

40

7938
8323
8440
8459
8363

45

8286
8236
8890
8432
8384

50

8452
8824
8621
8739
8812

50

8501
8601
8571
8465
8345

$5

1427
1456
1457
1442
1447

55

8750
9603
9149
8806
8875

55

8452
9032
8501
8682
8309

60

1444
1452
1441
1452
1452

60

8486
9397
8952
8782
8615

60

8362
9223
8553
8583
8221



4. SOLAR X-RAYS

"Solar X-Ray Emission on November 18, 1968"

by

D. M. Horan and R. W. Kreplin
E. 0, Hulburt Center for Space Research
Naval Research Laboratory
Washington, D. C. 20390

ABSTRACT

Solar x-ray data, obtained by the Naval Research Laboratory's SOLRAD 9 satellite
during the proton flare of November 18, 1968 are Presented. Presence of high energy
proton flux in the vicinity of the earth is indicated by charged~particle interference

with the satellite's x-ray sensors at lower altitudes and higher latitudes after the
flare.

Measurements of solar x-ray emission on November 18, 1968, Figure 1, by sensors aboard the
Naval Research Laboratory's SOLRAD 9 satellite (Explorer 37, 1968-17A) show the.Class 1B proton
flare to be the predominant X-ray event of the day. The top curve on the plot represents the solar
x-ray emission in the 8 to 20A band, and the next lower curve represents solar x-ray emission in the
1 to 8A band. In both cases a gray body solar emission spectrum [Kreplin, 1969] with a 2 x 10° K
color temperature was assumed in converting from detector current output to energy flux units. The
third curve from the top represents emission in the 0.5 to 3A band assuming a gray body spectrum
with a 10 x 10° K color temperature for the emitting solar region. Since solar emission in the 0.5
to 3A band is usually below the threshold level of the detector, the curve representing these data
is quite intermittent prior to the flare.

The x-ray emission is plotted in units of ergs/cm*/sec on a logarithmic scale. The abscissa
is linear with the integers denoting hours in Universal Time (UT). Charged-particle interference
with x-ray detectors, which can cause the plotted flux levels to be higher or lower than the actual
flux, is indicated by the lowest data curve. The ionization chamber current caused by the charged-
particle background is digitized and recorded as a "count". The number of "counts" is linearly re-
lated to the current generated in the 0.5 to 3A ionization chamber by penetrating charged-particles
when the detector is facing away from the sun. Counts of 10 to 15 indicate no particle interference
with the detectors. Counts of 20 to the maximum value of 127 indicate increasing amounts of parti-
cle interference.

pate SOLRAD 9 X-RAY MEMORY DATA o
681118 ral
_ nl ma ol iaaaeee el eee ed 16
ile PNP Ke AAI, in th ”
Bh 10} =f -— A oe eh 4 A 1e
an, a ae a eA
e ie a bere porta Naa \aed oo | 16
le \ 4 LH
Bsoillae | Ht La il ib bes Mage
Zi0
lth OD I i
i a ae eee a BO re en Vc 33 OM

Fig. 1. Solar X-ray Emission November 18, 1968.

23

8-20 FLUX

0-3 FLUX



8. GEOMAGNETIC ACTIVITY

"Note on 'On the Solar and Geomagnetic Events of October-November 1968' by M. C. Ballario
in World Data Center A - Upper Atmosphere Geophysics Report UAG-8, March 1970."

by

J. Virginia Lincoln
Space Disturbances Laboratory
ESSA Research Laboratories, Boulder, Colorado

This paper by M. C. Ballario covers the period of this Report UAG-9.

She states:
“Phe importance 2 flare of November 12 is followed by very quiet geomagnetic conditions.

On
the contrary, the sc geomagnetic disturbance of November 20 might be due to the importance 1 pro-
ton flare, since there are no correlated CMPs of positive plages.”

The flare referred to by M. C. Ballario is that from the TAU Quarterly Bulletin on Solar Acti-

vity of November 20, 1968, maximum at 0131 UT, position 218 63E, importance 1N with remark U=close
and somewhat parallel bright filaments (|| or Y shape), in McMath region 9780.

She associated with
this flare the geomagnetic storm of November 20 with Kp maximum about 1330 UT, Kp maximum value of
5- and delay time At, from flare to storm about 12 hours.

90



THU
ALE
RES
DUM
MCM

sou
INU
CHU
GOO
APA

OUL
DEE
OTT
CAL
BEG

SUL
POR
MTW
DUR
YAK

CHI
vic
SWA
LEE
KIE

LIN
cLI
HAL
MUN
2UG

DAL
JUN
WHI
HER
Pic

USH
TBI
ALM
BUE
MIN

CHA
KUL
HUA

HOUR O01

3946
6408
20301
1905
8345

2003
6032
5571
6137

472

3322
6050
2606
9978

22

7366
1738
2002
2297
1004

2166
5944
3086
66048
5630

3474
3618
34

5736
54304
$225
935
2296

156
1562
2152
2724
3673

6543
1178
1682

02

3943
6400
20261
1899
8382

2003
6041
5566
6150

479

3325
6104
2589
10012
28

7378
1736
1998
2289
1000

2185
5968
3066
6530
5615

3445
3628

48
4931
4524

5721
54275
5201
933
2286

131
1536
2163
2774
3567

6546

1172
1686

03

3956
6440
20362
1895
8354

2026
6016
5563
6145

474

3333
6110
2588
10003
12

7389
1736
2026
2302

993

2170
5973
3091
6539
5592

3444
3612
27

5737
54333
5171
932
2282

145
1550
2157
2798
3647

6555
1191
1676

04

3953
6396
20239
1884
8429

2033
6034
5570
6128

489

3315
6121
2609
9952

10

7387
1735
1995%
2289
991

2191
5944
3112
6513
5598

3450
3607

34
4902
4506

5727
54314
5234
932
2272

126
1546
2135
2749
3657

6546

1195
1676

Table 1

05

3930
6410
20213
1893
8441

2017
6027
5581
6135

477

3313
6089
2658
9966

35

7364
1733
1995
2277

986

2192
5965
3079
6511
5589

3438
3618
46

5733
54449
5185
931
2265

136
1546
2167
2760
3668

6538

1178
1680

2

5

4

06

3956
6441
0206
1886
8407

2033
6011
5568
6185

487

3304
6073
2636
9963

21

7376
1740
2020
2310
1008

2175
5957
3091
6541
5622

3436
3609

43
4868
4492

5736
4554
5172

929
2284

156
1540
2131
2722
3662

6516
1191
1676

o7

3939
6434
20307
1876
8380

2007
6035
5582
6158

485

3315
6090
2565
9949

8

7372
1725
2035
2318
1002

2163
5913
3091
6522
5593

3448
3604
49

5746
54622
5182
932
2280

184
1539
2150
2752
3648

6524
1193
1684

08

3938
6411
20203
1858
8330

2011
6026
5584
6176

488

3333
6083
2565
9923

10

7347
1725
2010
2283
1015

2212
5906
3107
6520
5579

3442
3602

23
4902
4494

5732
54420
5197
94)
2276

107
1562
2148
2831
3674

6517
1194
1689

09

3948
6413
20323
1860
8367

2019
6013
5565
6169

493

3311
6095
2581
9939

7363
1732
2018
2272
1003

2205
5937
3088
6518
5603

3453
3602
22

5759
54766
5218
945
2278

132
1558
2132
2756
3657

6522
1186
1695

10

3938
6398
20264
1872
8386

2023
5987
5584
6173

479

3300
6106
2586
9969

Q

7347
1715
2020
2289

999

2193
5945
3112
6533
5612

3440
3609

29
4888
4502

5761
54689
5195
932
2275

171
1552
2136
2746
3565

6522

1180
1673

ll

3978
6414
20287
1886
8533

2106
6018
5720
6318

477

3327
6244
2672
10240

12

7616
1728
2055
2319
1013

2232
6049
3121
6552
5593

3451
3686
B4

5768
54602
5247
924
2281

192
1584
2145
2773
3656

6514
1190
1678

12

4107
6611
20919
1946
8728

2205
6247
5754
6425

478

3343
6311
2673
10484

38

7833
1743
2117
2350
1006

2218
6081
3126
6588
5624

3458
3658

4888
4511

5768
54487
5258
934
2275

150
1576
2140
2776
3666

6509
1198
1676



FLARES

SHEPHERD BAY
SUNRISE AND
SUNSET AT 30 KM

1B 1B 1B

<> <4 oO
N21 W87 N20 weg S24 E57

T tT J Ty

lap
4/7 MeMURDO SOUND (SUN ALWAYS UP)

eS Fr (30 MHz)
=
s
3 SHEPHERD BAY
a 4 Homa)

ab

0

i ATS: DATA (BLAKE,

PRIVATE COMMUNICATION)

= tt
a
ws -
2
s
2+ 5 <E<21 MeV
s
Ss

" 21<E<70 MeV

103 L 1 L 1 4
00 12 00 12 00 12 00
} 11-18 } 11-19 i 11-26 ——»>|

UNIVERSAL TIME

85



"896T *8T 29quIeAOCN LN OOZT-O00T 204TY deed Je osvetoOUT kei oTwsoos Fo Jesup

°% *8Ta

Bod

a)

“LAGI OL LHDIY WOdd SHSVAYONT AWIL
*queozed ¢ sTenbe uotstatp [Tews euqo *AjTsueqUr zeTeos TeROTIAOA
*seqnuTu %_, sTenbe uotsTATp euO “°L°N UT SWTL feTeds [Te}UCZTIOH

“S961 ‘ST UAAWHAON ‘USATU daad YOM CUOOMA UALEW ALVA-ONILNNOD

Ramee ae’

Vadis

yy le he ees

Fe ee
‘ TATA ae ad Cee aie nay

Pra peel nal a

Bait jist

rere

62


"Comparison of Transpolar VLF Measurements with Riometer Measurements Made Within the Polar, Cap
During the PCA Event November 18, 1968"

by

K, Rinnert
Max-Planck-Institut fur Aeronomie, Lindau/Harz, Germany

The VLF signal of the transmitter NPG/NLK (18.6 kHz) is continuously monitored at Lindau/Harz
(German Federal Republic). The propagation path - with total length of 8,100 km - passes the arc-
tic polar cap and reaches approximately at midway its geomagnetically most northern latitude of 82°
Near this point is the riometer site at Godhavn. The cosmic noise of 30.5 MHz is received by a 2-
element-Yagi-antenna directed to the zenith. These measurements are carried out by the ionospheric
laboratory of the Danish Technical High School Lyngby in cooperation with the Max-Planck Institute
for Aeronomy Lindau.

The Figure shows the comparison of these recordings during the solar proton event of November
18, 1968.

At the top there is a representation of the changes of solar illumination along the propaga-
gation path NPG-Lindau. The great circle arc is scaled as the ordinate, the upper and lower border
correspond to the position of the transmitter NPG and to the receiver, respectively. The dashed
line marks the location of the riometer site at Godhavn and the dotted lines represent the inter-
section points of the propagation path with the zone of maximum auroral frequency. The curves show
the situation of the terminator at a height of 75 km taking into account a screening height of 30 kn
above the propagation path. The hatched regions represent nighttime conditions, that is, the solar
zenith angle is greater than 96.5°.

In the middle the cosmic noise recordings from Godhavn, Greenland (30.5 MHz) are shown. The
diode-current is recorded on a linear scale. At this time of the year the sun above Godhavn reaches
its smallest zenith angle of 92° at about 16 hours UT. The increase of absorption caused by the
proton impact starts at about 1135 UT. The riometer shows the biggest effect during "daytime con-
ditions” in the lower ionosphere. During nighttime conditions there is a relatively small enhance-
ment of absorption. Four days after the beginning of the effect the diurnal variations are normal
again.

The recordings at the bottom of the figure represent the field strength (logarithmic scale) and
the phase of the 18.6 kHz signal from NPG at Lindau. At 1040 UT on November 18, the signal strength
decreases rapidly, by at least 25 dB, beyond a certain threshold and the phase detection stays. Up
to the morning hours of the 20th of November the signal remains near this lower limit whereas the
diurnal phase change is quite normal even on the 19th. The field strength increases slowly during
the following days.

The attenuation of the VLF propagation during nighttime conditions especially is a very sensi-
tive indicator for additional ionization in low altitudes as it is produced by high-energetic protons
in the polar cap [Lange-Hesse and Rinnert, 1969]. ‘The recovery of the nighttime field strength takes
about 10 days with a time constant of about 3 dB per day. The phase is not very much affected, i.e.,
the diurnal changes are quite normal even if the absorption is still increased [Rinnert, 1967].

November 1966
NPG,

Gosnavn
Lingau|

0

i f -
hob & b hk & m b@ mH 2 & b&b & 8 & b DR
Pom FP mw

Be
8B

Fig. 1. Solar illumination, 30.5 MHz cosmic noise recordings at Godhavn, and amplitude and
phase recordings of NPG (18.6 kHZ) at Lindau, November 18-27, 1968.

86



"Explorer 34 Solar Proton Monitoring Experiment, Ep >10 Mev, November 17 - 28, 1968"

by

Cc. 0. Bostrom
Johns Hopkins University, Applied Physics Laboratory
and
D. J. Williams and J. F. Arens
NASA Goddard Space Flight Center

[The compiler has prepared the following paragraph and figure from the data routinely published in
"golar-Geophysical Data". ]

In Figure 1 the proton intensities in the energy range Ep 210 Mev from the Solar Proton Moni-
toring Experiment (SPME) are presented for the period November 17 to 28, 1968. These data are from
‘'Solar-Geophysical Data", No. 300, Part II, p. 91. The Descriptive Text issued as IER-FB 294 (Sup-
plement) to "Solar-Geophysical Data" describes these measurements on pages 64-69. An outstanding
event begins on November 18, and full recovery does not take place until November 26, 1968.

10%

10%

; IMP F SPME
10%

#/STER CMP SEC

10%

100+ + +“

ae al

a as
= ww
cc)

Fig. 1. Ep >10 Mev Hourly Averages.

31



Universal Time Location
Approx.
Max Mer Central | Duration | Importance | Meas. Area | Remarks
Start End Phase Lat Dist. Distance Min Sq. Deg.
1017-0 «1127 1033 N21 W87 0.998 70 1B 2,07 A 3335
1026 = 1235 1058 N20 w90 1,000 129 1B 1.66 AHVY 4116

Remarks

A = Eruptive prominence, base at >90° V =

H = Flare with high velocity dark surge ¥

Occurrence of an explosive phase
Onset of a system of loop-type promi-
nences

The first number is the number of stations reporting the individual maximum and
not necessarily the total number of stations reporting some part of the flare

event.

(For this flare there were 6 stations in the latter category.) ‘The

second number is the number of values entering the average importance, the
third the number of values entering the average measured area and the last
number the number of stations reporting at the time of the individual maximum
and not necessarily the total number of stations observing during the flare

event.

The sudden ionospheric disturbance events during the time of the flare were:

Wide Number of Station Reports by Type
Universal Time Spread LE-
Start End Max Imp. | Index SWF SCNA SEA SPA SPA SES SED
1026 1220 1050 3 5 3 1 3 2 2 3
1114-1236 —-1135 2 5 1 1 1

The worldwide solar radio emission outstanding occurrences were not published in "Solar~Geo-

physical Data" for this period.
the format in which they are now published.

The events of November 18, 1968 are therefore given in Table 2 in
The spectral data were published and are repeated here:

STATION DECIMETRIC BAND TYPE METRIC BAND TYPE
START UT END UT INT. START UT END UT INT.
WEISSENAU 1026.5 1034 3 ILIGG
1026.5 1050 3 Ty
1026.5 1105 3 IL
1045 1104 2 TIIGG,DP
1122.5 1126 1 iL

The magnetic activity throughout the period is indicated in Fig. 2 which presents the 27-day

musical-note diagram of Kp.

There is an sc on November 20 at 0904 UT reported by 49 stations

(ssc: 44 [A: 23; B: 21]; si: 4; pi2: 1) but the storm which followed was of short duration and of

only moderate intensity.

DAYS IN SOLAR ROTATION INTERVAL

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Ler ee See ee ee ee Ser ee Fee

PLANETARY MAGNETIC
THREE -HOUR -RANGE INDICES
Kp (after Bartels)
Kp till 1969 January 31
Ks (from Wingst ang Géttingen) tit Febr. 13



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"Pioneer 9 Solar Wind Velocity and Electric Field Data 8 November 1968 to 4 January 1969"

by

Ira M. Green and F. L. Scarf
Space Physics Analysis Department
RW Systems Group, Redondo Beach, California

[The compiler has prepared the following paragraphs from information submitted by the authors.]

Pioneer 9 was launched November 8, 1968. In Figure 1 is shown the trajectory plot of the space

probe from launch to January 4, 1969. The position of Pioneer 9 during November 18-20, 1968 is
indicated.

Figure 2 presents data from November 8, 1968 - January 4, 1969 from Pioneer 9. Intermittent
samples of the peak solar wind velocity in km/sec from the plasma probe are given in the top por-
tion of the graph, Electric field data at the approximate frequency of 100 Hz are given in the
center of the graph as the broadband potential amplitude, $, in millivolts. Kp-indices are plotted

at the bottom of the graph. Solid triangles indicate the times of ground sudden commencements and
open triangles denote sudden impulses.

Yse
1200 Rp P>—
| PIONEER 9
JAN 4, 1969
DEC 8, 1968
800
400 NOV 18-20, 1968
Nov ll, 400 800 1200 Re
: we Xcp

Fig. 1.

Trajectory of Pioneer 9, November 8, 1968 to January 4, 1969.

40



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19


3. SOLAR RADIO EVENTS

"On the Type IV Burst of November 18, 1968"

by

A. Kriger
Central Institute for Solar~Terrestrial Physics (HHI)
Berlin-Adlershof, G.D.R.

The type IV burst of 18 November 1968 was a somewhat late and isolated event in an active re-
gion which had had a 6-configuration since November 8, 1968. ‘The flux ratio of the s-component
S94o0/S1500 Was greater than 1,5 from November 9, 1968. Perhaps these circumstances contributed,
too, to the outstanding energy output of this event.

Selected records of the radio burst observed at the HHI are shown in Fig. 1, Because of the
position of the source region on the very western limb of the sun only those burst components could
be observed, which were not subject to a large center-to-limb variation. Therefore, large parts of
the type IVmB burst are expected to be missing. In this way, the burst does not exhibit such long
duration and high intensities as it might be expected from the associated proton event. Neverthe
less, the right-handed polarization of the burst components at 40 MHz indicated an emission of the
ordinary component of the magneto-ionic theory, if the leading spot hypothesis is accepted, so that
to a certain extent, in this frequency region type IVmB components were recorded. At shorter wave~
lengths also moderate type IVmA components and the type IVcm burst have been observed. ‘Type IVdm
emissions which are characteristic for low-energy events are not present here [cf. Bohme and
Kruger, 1969; Castelli and Aarons, 1968]. A spectral diagram of the event is given in Figure 2.
From this picture the main components of the burst again can be seen.

Acknowledgement

The assistance of Mr. K. H. Fricke for the construction of the spectral diagram is gratefully
acknowledged.

REFERENCES
BOHME, A. and 1968 HAI Suppl. Ser. Solar Data, Vol. I, No. 3.
A. KRUGER

CASTELLI, J, P. and 1968 Astrophys. J., 153, 267.

J. AARONS

14



Table of Contents (Continued)

7. LONOSPHERE
"Observations in the Arctic and Antarctic of the 18 November 1968 Solar
Cosmic Ray Event"
(A. D. Goedeke and A. J. Masley)
"Comparison of Transpolar VLF Measurements with Riometer Measurements Made
Within the Polar Cap During the PCA Event November 18, 1968"
(K. Rinnert)
"Ionospheric Absorption Around November 18, 1968"
(i. Schwentek)
"Radio Propagation Quality Indices November 15-30, 1968"
(8. Beckmann)

8. GEOMAGNETIC ACTIVITY
"Note on 'On the Solar and Geomagnetic Events of October-November 1968!
by M. C. Ballario in World Data Center A - Upper Atmosphere Geophysics
Report UAG-8, March 1970"
(5. Virginia Lincoln)
"Equatorial Dst"
(M. Sugiura and S. J. Cain)
"Geomagnetic Disturbances During the Period November 16-21, 1968 Associated
with the McMath Plage Regions 9760, 9772 and 9780"
(K. Kawasaki and S.-I. Akasofu)

83

86
88
89

90
91

92



and e,, @g, eg are unit vectors in the r, 6, and $ directions with j being the current per unit
length in the'neutral sheet in electromagnetic units and tT being the geomagnetic time expressed in
degrees measured eastward from geomagnetic midnight.

The Williams and Mead parameters to adjust the external field configuration utilized in these
calculations are as follows:

ty (the subsolar point) = 10 R (earth radii),
R (the inward termination point of the neutral sheet in the tail) - 10 Re
R, (the outward termination point of the neutral sheet in the tail) = 40 R,.

Bog (the tail field associated with the current sheet) adjusted to 40 y.

The model of the magnetopause used is a surface of revolution about the earth-sun line com-
posed on the day side by a hemisphere of xadius of 13.9 Ry centered at -3.5 R, and extended into
the truncated cone whose generators form an angle of 15.3° with the earth-sun line. This model is
most appropriate for equinox conditions and does not include seasonal variations or ring currents.

To determine this set of asymptotic directions of approach, an anti-particle of specified ri-
gidity was initiated in the vertical direction at an altitude of 30 km and traced until the trajec-
tory either penetrated the magnetosphere boundary ox extended up the tail a distance greater than
25 earth radii. The direction of the velocity vector at the magnetospheric penetration point was
calculated in terms of a geocentric coordinate system and the asymptotic direction of approach was
determined.

The following tables contain the asymptotic directions of approach for selected high latitude
neutron monitors. Negative asymptotic longitudes indicate that the particle velocity vector does
not cross the Greenwich meridian, Longitude values larger than 360 degrees are indicative of a
large longitudinal drift of the particle as it traverses the magnetic cavity. If the particle or-
bit intersects the solid earth (i.e. forbidden) it is designated by an R; if the trajectory fails
to reach a solution by 15,000 iterative steps, the result is denoted by an F and presumed to be
forbidden.

When these results are compared with any of the previous published calculations utilizing only
the internal field [Hatton and Carswell, 1963; McCracken, et al., 1965; Shea, et al., 1965; Shea,
et al., 1968] significant differences in asymptotic directions are evident at low rigidity values.
From our analyses of asymptotic directions calculated using both internal and external sources, we
have found that these differences axe primarily the result of the addition of external sources to
the field in the earth's magnetic cavity. The differences resulting from the use of various inter-
nal geomagnetic field models are considerably smaller.

REFERENCES

GALL, RUTH 1968 Daily Variation of the Asymptotic Directions of Cosmic
Rays, J. Geophys. Res., 73, 4400.

GALL, RUTH, 1969 Directions of Approach of Cosmic Rays for High Latitude

JAIME JIMENEZ and Stations, J. Geophys. Res., 74, 3529.

A, OROZCO

HATTON, C, J., and 1963 Asymptotic Directions of Approach of Vertically Inci-

D. A. CARSWELL dent Cosmic Rays for 85 Neutron Monitor Stations,

Atomic Energy of Canada, Ltd., Report No. AECL-1824,
August 1963.

IAGA COMMISSION 2, 1969 International Geomagnetic Reference Field 1965.0,
WORKING GROUP 4 J. Geophys., Res., 74, 4407.

McCRACKEN, K. G. 1962 The Trajectories of Cosmic Rays in a High Simulation
U. R. RAO, and of the Geomagnetic Field, Mass. Inst. Technology Tech.
M. A. SHEA Rept. 77, August 1962.

McCRACKEN, K. G., 1965 Cosmic Ray Tables, IQSY Instruction Manual 10, IQSY
U. R. RAO, Committee, London,

B, C, FOWLER
M. A. SHEA, and
D. F. SMART

69



During the first ten hours of November 18, Figure 1, background solar x-ray emission in the 1
to 8A and 8 to 20A bands was steady at high values. Two small x-ray events occurred with peak flux
levels of the first at 0040 UT and peak levels of the second hidden by satellite night but occur-
ring after 0405 and before 0441 UT. ‘These events correspond to an unconfirmed normal subflare at
0036 UT*, and two unconfirmed Class 1 flares and a normal subflare whose maximum phases occurred at
0426, 0431, and 0444 UT, respectively. A third small event may have attained peak values between

0722 and 0759 UT. This would correspond in time to a confirmed faint subflare with a maximum phase
at 0750 UT.

Sharply rising flux levels marking the beginning of the proton flare were first observed at
1026 UT. A small peak in the 1 to 8A band emission occurred at 1029 UT, The principal optical
maximum phase was observed at 1033 UI. A second, larger x-ray peak occurred between 1039 and 1115,
but the exact time is unknown because of satellite night. A secondary optical maximum phase was
observed at 1058. The x-ray emission from the event decayed quite steeply between 1115 and approxi-
mately 1400 where a more gradual decay commenced. The x-ray emission from the proton flare does not
merge with background x-ray levels until approximately 0500 UT on 19 November, Figure 2. A sharp
x-ray event which peaked at 2315 on November 18, corresponds to an unconfirmed brilliant subflare
with a maximum phase observed at 2312 UT.

Since the predominant event of the day is known to be a proton flare, the behavior of the low-
est data curve on the plots is especially interesting. The plot for November 17, 1968, Figure 3,
shows the preflare behavior of this data curve, which indicates charged-particle intereference with
the 0.5 to 3A ionization chamber when the detector is facing away from the sun. Note that the dura-
tion of charged-particle interferences during the first 14 hours of the day was approximately ten
minutes, but during the final ten hours of the day it increased to 20 to 30 minutes. This increase
in the time during which charged-particle interference occurred is associated with the passage of
the satellite through a larger portion of the South Atlantic anomaly. The same pattern is qbserved
in the plot for November 18, Figure 1. However, the plot for November 19, Figure 2, does not show
the same pattern of charged-particle interferences.

pate _ __SOLRAD 9 X-RAY MEMORY DATA _ ag
681119 :
we de oe ee pd ict
i aa ate ah | “TS I, sty 1g
S16 an ate - + ie
: ll Moat a ;
+10" T T HE al ty 7a aa 7H
1d" po 10
2 | ty al sal th :
Said La " il if Lit rf a F 10
5 TUE,
gro we e108 ps ie 17 1B 18 20 2122 as

Fig. 2. Solar X-ray Emission November 19, 1968.

*A1l references to Flare Class were obtained from "Solar-Geophysical Data", IER-FB-297, May 1969,
published by ESSA Research Laboratories, Department of Commerce.

24

@-20 FLUX

0-3 FLUX



The upper row of sketches in Figure 1 shows characteristic features identified in these
flickering FeI films. The outer contour encloses the region where the flicker is more prominent
than the squirming motion of the quiet chromosphere. With good observations this region corre-
sponds to the HY plage. ‘The second contour defines regions of stronger flicker (and brighter
plage). In a few cases a third contour is shown where the region appears bright relative to its
surroundings on one frame, and relatively dark on the next frame; these small regions seem to
correspond to the transition between plage and visible sumspot on the HO films, Well developed
sunspot umbras are underexposed on these films but strong flicker is usually present in the sur-
rounding penumbra. Comparing these contours to a Sacramento Peak high resolution (5 arc sec)
magnetogram kindly provided by David Rust, we can guess that the three contour levels correspond
roughly to 40, 60 and 160 gauss as measured by a conventional magnetograph with square aperture
5 arc sec on each side. However, because of small-scale structure associated with the flicker,
the 53244 Fel filtergram films are thought to flicker only where the line-of-sight field exceeds
100 gauss. This region was one of the first observed at Lockheed with the Fel filter, under far
less than optimum conditions. Consequently, day-to-day changes in areas of the contoured regions
in the sketches in Figure 1 probably depend as much on observing conditions as on the actual evo-~
lution of the magnetic region. Also, the detection and interpretation of line-of-sight fields
becomes uncertain as a region approaches the limb, Picturing magnetic lines of force arching be-
tween a western leader spot and an eastern follower, one can see that as solar rotation carries
the region from east limb to west limb, the line of polarity reversal, where the observer's line-
of-sight is normal to the field direction, will move from west to east across the region. Also,
the polarity closer to the limb is undetectable when the opposite polarity is identifiable. Ex-
amples of this may be seen in the Mount Wilson magnetograms published in “Solar-Geophysical Data."

An eastward drift of the polarity reversal line from November 10 to 14 is probably caused by
solar rotation. The change in direction of the polarity reversal line is not so readily explained.
Observations on November 13 show this line to be typically oriented, more or less parallel to the
meridian, But on November 16, regions of opposite polarity are separated by a boundary running
more nearly parallel to the equator.

Photographs and drawings in "Solar-Geophysical Data" show that during this period, from
November 13 to 17, spots and plage develop northward from the largest spot while the eastern part
of the region appears to decay (at least partly because of its approach to west limb). Thus the
“center of gravity" of leader spots, of leader plage, and of magnetic field of leading polarity
all swing around from east of the large follower spot to north of it. With some faith and imagi-
nation in identifying individual spots from day to day, apparent rotation can be seen also in the
daily sunspot drawings published in Solnechnye Dannye. ‘hese are reproduced in the lower line of
Figure 1.

From these discontinuous data we can neither identify individual spots surely from one day
to the next, nor establish proper motions. The appearance of many small spots north of the large
spot on the 15th, and the parallel development of bright HO plage in this region, lead us to be-
lieve that the most significant change is the growth of this northern region, accompanied by de-
cay of the eastern region, much as described for the general case by Martres et al. On the other
hand, Sakurai [1967] describes the east-west direction of the line of polarity reversal, and the
rotation that leads to this orientation, as characteristic of regions that produce ground-level
cosmic ray events (GLE). He finds that, with few exceptions, the line separating the two mag-
netic polarities in these sunspot groups rotates in the direction that initially brings the lead-
er spot to the poleward side of the follower. Sakurai proposes that exceptionally strong magnet~
ic buoyancy in these regions leads to rotation that twists the magnetic lines of force into a
configuration that is particularly effective for storing energetic charged particles.

A quantitative estimate of the rate of rotation of the line of polarity reversal seen on the
filter magnetograms was made by measuring on successive days its inclination to the meridian that
passes through the sunspot group (see the inserted sketch in Figure 2). Because of the apparent
curvature of meridians near the limb, the actual measurements on the Lockheed films were made
with the geographic north~south line as reference. These were reduced by subtraction of the
angle Py (taken from the American Ephemeris and Nautical Almanac) changing the reference line to
the solar rotation axis. If, in heliographic coordinates, B, is the latitude of the center of
the solar disk, B the latitude of the sunspot group, and A its central meridian distance, the
angle M from the rotation axis to the tangent to the meridian through the group is defined by:

tan M = sin B sin x -
cos B cos By + sin B cos A sin By

We used B, = 3°, B = 19°, and h = ea (time of observation - 1148) to find the value of M for

each measurement. ‘This was subtracted from the reduced measured angle to get the inclination of
the line of polarity reversal to the meridian, plotted in Figure 2 as solid line and crosses.

10



SELL
NOVEMBER 18,1968
R(Bev))
sol Hi SUDDEN RISE OF THE X-RAYS |
+ DALLAS
4.0F 4
ly
n
307 = —w——e- CLIMAX 4
a
$
3 +——*- LEEDS
20+ 8: J
aay
a)
is:
: ° CALGARY
10+ = ee DEEP RIVER 4
+»  GOOSE BAY
H a= SYOWA BASE
: —+—e— INUVIK
0.0F H —a——e-— ALERT 4
FP
7020 «1040 «1100 += 120.~=« 140
U

Fig. 3. Onset times of cosmic-ray increases by energy range
compared to HO explosive phase and sudden rise of
x-rays, November 18, 1968.

REFERENCES
VAN ALLEN, J. A. 1967 J. Geophys. Res., 72, 5903.
KRIVSKY, L. and 1969 Private communication.

2. SVESTKA

29



COLLEGE

qT
5007

L
SODANKYLA ape enamine a

LEIRVOGUR Veen a

GREAT WHALE

RIVER ei ae

MEANOOK

L i | i 1 1 i 1 i i i I
00 02 04 O6 O8 10 12 14 16 18 20 22 24

18 NOV 1968, HOURS, UT

Fig. 4b. H-component magnetic records of five high latitude stations for
November 18, 1968.

The decrease in the H-component associated with this disturbed period began about 1200 UT,
November 17 reaching a minimum of about 100 gammas around 20 UT November 17; by 1200 UT of November
18 the storm was well in its recovery phase. Three rather large positive bays were recorded at low
latitude stations in the Asian sector (Figures 3a and 4b). Bays are known to occur when intense
polar substorms are in progress along the midnight sector of the auroral oval. The records for
high latitudes, Figures 3b and 4b, although lacking Siberian data, indicate polar substorms were in
progress during the main and recovery phases of the storm.

‘These polar substorms were especially intense when the ring current became asymmetric. This
can be seen particularly during the recovery phase of the storm when the high latitude stations
whose records were available were in a favorable position to record polar substorms along the mid-
night portion of the auroral oval. This rough direct correlation between polar substorms and ring
current asymmetry is less evident during the main phase decrease probably due to the lack of Siber~
ian data.

Flares 14 through 18 did not appear to have produced significant geomagnetic activity except
possibly for the few si which occurred during the latter part of November 17 and November 18.

At approximately 1630 UT on November 18, a fairly isolated large si was observed (Figure 4a),
The simultaneous high latitude records (Figure 4b) show very little disturbance. This event might
be classified as the beginning of a magnetic storm which did not develop a main phase, but its
rise was quite gradual ( 20 minutes). This large si could have been caused by any one of the
Flares 14 through 18. However, its large amplitude is suggestive of a central meridian flare
akasofu and Yoshida, 1967/. Of the Flares 14 through 18, Number 18 occurred closest to the cen-
tral meridian. No noticeable Forbush decrease was associated with the si ["Solar-vcophysical Data"
January, 1969).

By the latter part of November 19, the geomagnetic storm which began on November 16 had fully
recovered (Figures 5a and b) and this relatively quiet condition continued through the early part
of November 20 (Figures 6a and b).

‘The second geomagnetic storm of the period of study began with a large ssc at 0904 UT on
November 20 (Figures 6a and b). Note a “precursor''-like si activity which preceded the ssc. ‘The

98



"Equatorial Dst"
by
M. Sugiura and S. J. Cain

Goddard Space Flight Center
Greenbelt, Md.

The Figure presents the hourly equatorial Dst for November 10 to December 10, 1968.
indices for the same period are also plotted on the Figure and the sudden commencements are indi-

cated.

The table below
Greenbelt, Maryland,

The Kp

is reproduced from the NASA Report X-612-70-3, Goddard Space Flight Center,
January 1970 entitled "Provisional Hourly Values of Equatorial Dst for 1968"

3 oMaTe
230 28
-210 -192
-81 -91
“73-69
-40 -42
-29 -26
-13 -28
-18 -20
-34 -36
2290-18
-28 -27
w17 18
+38
“7-6
fae’
ron
-s 8
-66 61
“27-27
“7-8
719 -18
-23 -22
2300
1116
2s oat
“toot
“4-6
“5-7
a7
a8
1 <3

by M. Sugiura and S, J. Cain.
UNIT=GAMMAS
1 2 3 & >» © 7 8 9 19 41 42 13 18 15 18 17 18 19 20 21 22
-138 -121 -112 =109 -109 -1v0 -108 -107 0-101 788-123 - 128 =131 -129 -159 -154 -183
164 “172 “171 179 ~187 -150 ~156 -156  -153 -105 +97 95 -79 -~61 -5$ ~59 -57
=SS -lud -118 -103 -100 -101 -97 ~90 -86 -70 -71 -66 -S9 ~63 -66 -67 -70
-63 -oe ~ol “61 =57 -45 -47 -57 -61 -s2 -s0 w46 983-83 at aR 86
TAR 84 45 93 48 08-46 87 -46 -31 -35 35-34 -25 -25 -2r -27
-28 -23 -20 ~23 -29 -30 0-28 -25 -21 20 w19 -17 -12 -15 -18 13
737 wa - 3a -40 -S3 -4a -39 -35 30-28 -23 -23 -24 -21 -18 -18
-19 -19 -19 ver -24 -27 -25 “28 ~32 -32 -29 -27 -20 -2l -30 -32
-38 -se -31 ~30 -23 -2t -20 -24 -35 -36 -33 +26 -23 -21 -19 ~-20
-z20 -19 ~19 +20 -z5 ~28 ~29 “27 “130-18 “22-25 +27 -24 -27 -29
22-20 -32 -26 -2? -se -38 29 “25 -28 -29 ~30 -32 -26 -23 -23 -21 +23 +20 -15 “15 ~16
TIE 418 “18 10 -17 -13 =18 -16 w13 13 1a -16 W135 -15 -12 0-8 ee ee ee ee
2-201 2-1 =a -3 m2 Bo o2 so =f 0 2 2 = ee ee
“7-8 “8 -2 1 -2 -0 3 Ss 4 5 6 8 12 13 10 9 3 7 6 6 =3
$ 10 8 10 ww 10 9 3 3B 2 1 2 3 2 4 =o “300-2 0-1 19 1
roo. 8 to-r ~  0 8 6 20 27 37 37 33 4% 50 49° 430 42 330 19S
6 -s 3 Lb 4 -4 -100 -7 w1a 915 -11  =9 -5) -2 m1: ~22 29-42 +42 -44 -57 -65
78a -50 -53 -39 -01 ~65 +67 70 67 -83 -s8 ~96 -43 -37 -29 -25 -IS -8 etl 13 15 -22
s2e -23 -24 -27 -30 =33 -35 ~30 ~23 217 -16 -ig -19 -13 -11 0-9 “7 -8 -@  -8 -12 -10
S830 6 18 17 ws men? ~3 18 «21 «17 12 3-20-36 -33--37 +40 =39 --31 0-24
<17 -14 -15 -19 -21 -20 ~26 -29 -27 ~26 -25 -28 -21 -19 -20 -24 -25 -28 -23 -18 -18
-20 -19 -17 <15 -13 11 ~18 =16 -19 -20 -16 -13 -110 -1090 -5 0 =1 en ee ee
-c -2 -8 -8 -10 -6 -3 ~6 8 -12 -11 -10 -s -3 -1 2 4 8 0 9 8 8
20 44 19 16 1b 15 17 18 19 19 17 47 15 15) 8B 19 29 28 28 28 25 25
36 12 18 16 18 47 15) 28 ie 13 8 Gt “3-0-3 -7 -3 0 =1
bo 3 8 8 8» 2D ww 9 4 0 -3 2 4 4-0 30-300 2-2 3
a a as “9-9 5-8 34 3 6 8 -7 =11 =10
-S 7-8-3 =e -e Bt “300-8 912-120 -9 -30 3 “3001 0-7 =2 0 58
@ te 42 10 5 6 8S 2 re | “3 ons 0 1 2 3 5 4
a 6 &§ 2 1 & F B es S$ 6 6 1 es 3B 2 “1 -2 -3 1
1968
NOVEMBER DECEMBER
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 2930 1 2 3 4 5 6 7 8 9 10
5 T T_T

-120F pst 4
-140 === Kp

-160f- * SUDDEN COMMENCEMENT
-180

Fig. 1

Hourly equatorial Dst November 10 - December 10, 1968.

91



120% T

Meridion
oor > wis

- oS
Boe SEE J
60° 4
Ang}
role Choe
40°— Polarity. Reversal -

20° /

o°}— ON - —
6 — —>o=0
ee SA “
“a o~ 2 yy 4
aple  d
T 8 9 10 Il 12 13 14 15 16 7 18 19
1968 November , Day Flare

Fig. 2. Rotation of the sunspot group prior to the flare of 1968 i
h u November 18. The inset sketch
shows schematically the heliographic meridians and parallels of latitude, along with line

of polarity reversal, which separates regions of opposi
of po posite polarity, and the i
joining the leader and follower sunspots. . ” magnetic axis,

+ + Angle from meridian to line of polarity reversal, measured on Lockheed
filter magnetograms.

O ----~ © Angle from parallel of latitude to magnetic axis, measured on Lockheed
filter magnetograms.

@-——© Angle from parallel of latitude to magnetic axis, measured on drawings

from Solnechnye Dannye.

We also measured on the Lockheed Fel films the direction of the magnetic axis, the line join-
ing the follower and leader sunspots. The angle, plotted as open circles and dashed line in Fig-
ure 2, is the inclination of the axis to the parallel of latitude through the sunspot group. The
inclination P of the parallel of latitude is found from: tan P= tan A sin Bo. The systematic
difference between the two angles just shows that the line of polarity reversal is not exactly
snormal to the magnetic axis.

Finally, the inclination of the magnetic axis was measured for the published sunspot drawings
taken from Solnechnye Dannye. These values are plotted as solid circles and dashed line in Figure
2. The rather erratic variation of the angle measured from the published data may arise from un-
certainty in identifying the main leader spot. Each set of measurements shows the same trend:
the angle changes little until late on the 13th, then increases at a fairly steady rate, between
25° and 35° per day. If we extrapolate this curve to the time of the flare, at November 18.4, we
would guess that the angle attains a value of about 135°; this would put the original leader spot
of south polarity behind the original follower, and closer to the equator, with the magnetic axis
inclined at about 45° to the equator. Of course, there is no evidence that the apparent rotation
continues at this rate. ‘The direction of the apparent rotation is that expected from differential
rotation; if the leading spot is at higher latitude than the follower, faster solar rotation near-
ex the equator will carry the follower toward and past the leader. The actual motion is much fast~
er than the difference in solar rotation rate for these close pairs of spots, so this observation
is probably irrelevant except as a mnemonic for the direction of rotation.

11



COLLEGE

T
s0or
1
SODANKYLA —

LEIRVOGUR

GREAT WHALE
RIVER ft NAN eye
MEANOOK ey

L i i 1 i i 1 t 1 1 1 1 J
00 02 04 06 08 to 12 14 16 18 20 22 24

17 NOV 1968, HOURS, UT

Fig. 3b. H-component magnetic records of five high latitude stations for
November 17, 1968.

ae

HONOLULU

KAKIOKA

- TANGERANG

TASHKENT SAY Qo oe
Jer a
“SAN JUAN

L L 1 J 1 i i 1 1 1 L j

00 02 04 O06 oO8 10 l2 14 16 18 20 22 24
18 NOV 1968, HOURS, UT

M'BOUR

Fig. 4a. H-component magnetic records of six low latitude stations for
November 18, 1968.

97



The growth of the main phase was observed in the afternoon-evening sector (Kakioka (22 LT),
Tangerang (20 LT), Tashkent (18 LT) and M'Bour (12 LT)). However, it was not observed in the morn-
ing sector (Honolulu (03 LT) and San Juan (09 LT)). San Juan observed the later part of the main
phase after 16 UT, when it moved into the afternoon sector. However, by the time Honolulu reached
the afternoon sector, the main phase was near the end of-its recovery. Thus, no large main phase
decrease was observed at Honolulu during this brief storm

O£ the remaining flares (Numbers 19 through 27) only Flares 19 through 22 were likely to have
caused the ssc of the second geomagnetic storm. The amplitude of the ssc and the accompanying
Forbush decrease (about 4%) were more indicative of a central meridian or eastern limb flare rather
than a western limb flare. However, the central and eastern limb Flares 19, 21 and 22 were not in-
tense. Flare 20 although not significantly more intense optically was associated with large in-
creases in solar protons and x-rays among others [Venkatarangan, et al., 1969]. Moreover, the high
latitude magnetic records (Figure 6b) show significant polar substorm activity at the time of ssc
and return currents from the high latitudes may have enhanced the amplitude of the ssc at low lati-
tudes. Thus, it is likely the western limb Flare 20 of M9760 was responsible for the geomagnetic
storm of November 20/21, 1968.

Flares 23 through 27 appear to have produced only minor worldwide magnetic disturbances during
the latter part of the period under study.

Acknowledgement

National Science Foundation Grant GA-1703 and the efficient service of Mr. W. Paulishak of
World Data Center A for Geomagnetism in providing magnetograms made this study possible.

REFERENCES
AKASOFU, $.-I. and 1967 The structure of the solar plasma flow generated by
S. YOSHIDA solar flares, Planet. Space Sci., 15, 39-47.
HAURWITZ, M. W., 1965 Interplanetary magnetic field asymmetries and their
S. YOSHIDA, and effects on polar cap absorption events and Forbush
S.-I. AKASOFU decreases, J. Geophys, Res., 70, 2977-2988.
VENKATARANGAN, P., 1969 Solar flare increases in cosmic ray intensity on
D. VENKATESAN, and November 18, 1968; February 25, 1969; and March 30,
J. A. VAN ALLEN 1969, U. of Towa Report, 69-47.
YOSHIDA, S. and 1966 The development of the Forbush decrease and the geo-
S.-I. AKASOFU magnetic storm fields, Planet. Space Sci., 14, 979-
986.

USCOMM-ESSA-ASHEVILLE-4-25~70-1100

102



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ALERT, CANADA

Geographic Latitude - 82.50 N

Geographic Longitude ~ 62,

UT = 1100 LT = 0651
Geomagnetic Time = 1400

33 W

Rigidity Asymptotic
(cv) LAT LONG
20.00 82.74  ~23.74
15,00 81,35  -22.78
10,00 80.40 ~28.36
5.00 78.37 -19.87
4,00 78.25 -18.83
3.00 76,00 -18,70
2.00 73.08 -16,18
1,00 64.45  -20.10
0.90 62.76 20.80

THULE, GREENLAND

Geographic Latitude - 76.55 N
Geographic Longitude - 68.84 w

UT = 1100 LT = 0625
Geomagnetic Time = 0829

Rigidity Asymptotic
(cv) LAT LONG
20.00 74.34  -42.45
15,00 72.09 -42.96
10.00 70.17 =49,49
5.00 67.93 -50.79
4,00 67.79 -53.74
3.00 65.72 -55.75
2.00 63.70 -58.84
1,00 57.23 -69.84
0.90 56.06 ~71.73

DUMONT D'URVILLE, ANTARCTICA

Geographic Latitude - 66.67 $
Geographic Longitude - 140,02 £
UT = 1100 LT = 2020
Geomagnetic Time = 2226
Rigidity Asymptotic
(ev) LAT LONG
20,00 ~67.48 159,20
15.00 -66,60 164,06
10,00 ~64,73 170.07
5.00 -60,97 181.73
4,00 759.30 © 186.25
3.00 ~56.33 192.93
2,00 -49,.65 203.68
1,00 5.76 © 215.73
0.90 0.00 210.82

71

RESOLUTE, CANADA

Geographic Latitude - 74,69 N
Geographic Longitude ~- 94.9] W
T= 1100 LT = 0440
Geomagnetic Time = 0404

Rigidity Asymptotic
(av) LAT LONG
20.00 68.92 -83.44
15,00 66.86 -84,50
10.00 64.24 88,28
5.00 59.44 -91.69
4,00 57.58 ~93.44
3.00 54,40 ~95.32
2.00 48,94 =98.42
1,00 34,82 106.15
0,90 32.08 -107.65

VOSTOK, ANTARCTICA

Geographic Latitude - 78.47 §
Geographic Longitude - 106.87 &
UT = 1100 LT = 1807
Geomagnetic Time = 0940

Rigidity Asymptotic
(cv) LAT LONG
20.00 ~69.56 54.58
15,00 ~70.31 41.81
10.00 ~74.06 33.56
5.00 ~70.61 25,22
4,00 ~69.75 28.38
3.00 ~68.80 19.32
2.00 ~64,27 12.73
1,00 -57,50 -2,29
0.90 ~56.02  ~4.4h

MCMURDO, ANTARCTICA

Geographic Latitude 7 77.85 $
Geographic Longitude - 166.72 E
UT = 1100 LT = 2207
Geomagnetic Time = 0343
Rigidity Asymptotic
(gv) LAT LONG
20,00 ~84,16 291.47
15.00 -79.64 283,14
10,00 -75.80 267.78
5.00 ~69.35 271.07
4.00 -68.07 272.56
3.00 -63.76 270,86
2.00 -56.60 272.52
1,00 ~A1,18 270.60
0.90 ~38,24 270.18



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main phase decrease began about 13 UT reaching about 100 gammas some six to ten hours after ssc; by
midday of November 21 recovery was well underway (Figures 7a and b).

HONOLULU eee
KAKIOKA _oe—-_—«_—_—_ner oro

4

TANGE RANG

TASHKENT ee ee

]=y vad OSTM oo
wigouR 9

SAN JUAN eee

t i 1 L 1 1 L L 1 1 1 1 J
oo 02 04 O06 08 ite} 12 14 16 18 20 22. 24
19 NOV I968, HOURS, UT

Fig. Sa. H-component magnetic records of six low latitude stations for
November 19, 1968.

COLLEGE n\n

SODANKYLA YO

LETRVOGUR may yen pt AS

GREAT WHALE

RIVER EN NN et

MEANOOK aaa ee

L L i L 1 1 i il 1 L 1 1 i} i
00 02 04 06 08 10 2 4 6 IB 20 22 24 |

19 NOV 1968, HOURS, UT

Fig. 5b. H-component magnetic records of five high latitude stations for
November 19, 1968.

i
4
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INUVIK

NEUTRON MONITOR

fable 3 (Continued)

68e21N 133643W

18-NM-64

REAL COUNTS 100 TIMES TABULATED COUNTS

CANADA

FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 18>

TIME
Uele

900-1000
1000-1100
1100-1200
1200-1300
1300-1400
1400-1500
1500-1600
1600-1700
1700-1800
1800-1900
1900-2000
2000-2100
2100-2200
2200-2300
2300-2400

os

6009
6046
6425
6120
6114
6090
6072
5993
6150
6060
6054
6126
6108
6048
6042

10

5972
5985
6388
62il
6047
6102
6144
6060
6042
6024
6078
6012
6066
6072
6144

FORT CHURCHILL

1968

15

6009
5973
6327
6144
6041
6126
6090
6108
6060
6108
6000
6036
6102
5988
6060

MINUTES AT END

20

5966
5997
6266
6181
6078
6053
5993
5999
6017
6011
6108
6120
6114
6090
6096

25

6003
6022
6260
6199
6065
6114
6114
6048
6017
6036
5963
6114
6054
5988
6030

58675N

NEUTRON MONITOR NM~64

30

6027
5979
6236
6114
6126
6138
6054
6090
6017
6060
6108
6138
6048
6036
5964

OF INTERVAL

35

5990
6004
6224
6163
6053
6035
6102
6017
6126
6060
6108
6102
6078
6012
6120

265e90E

BAROMETER REFERENCE 1010 MILLIBARS

ATTENUATION COEFFICIENT 13762 MILLIBARS

REAL COUNTS 40 TIMES TABULATED COUNTS

40

5972
5955
6193
6120
6126
6120
5981
6066
6120
6048
6156
6102
5994
6180
6060

45

5972
6004
6205
6108
6114
6060
6096
6054
6060
6084
6102
6084
5994
6066
6090

CANADA

FIVE-MINUTE BAROMETER CORRECTED HOURLY RATES

NOVEMBER 18% 1968

TIME
Uele

900-1000
1000-1100
1100-1200
1200-1300
1300-1400
1400-1500

05

1400
1412
1491
1434
1401
1407

10

1393
1419
1471
1434
1400
14624

15

1384
1398
1450
1411
1416
1426

MINUTES

20

1399
1408
1444
1425
1416
1419

25

1400
1421
1437
1427
1433
1405

AT END

30

1391
1382
1421
1408
1411
1411

50

OF INTERVAL

35

1383
1396
1424
1422
1412
1424

40

1395
1414
1432
1428
1416

45

1400
1398
1432
1393
1399
1423

50

5942
6052
6236
6132
6078
6035
6023
6023
6036
6096
6048
6024
6126
6084
6012

50

1403
1418
1415
1413
1412
1410

55

6003
5991
6102
6169
6132
6065
6017
6035
6060
6030
6036

6084

6030
6054
6120

5948
6230
6077
6053
6078
6023
6090
6023
5999
6126
6054
5994
6042
6042
6108

60 AVERAGE

5984
6020
6245
6143
6088
6080
6065
6043
6059
6062
6068
6078
6063
6055
6070

55 60 AVERAGE

1395
1542
1419
1413
1411
1407

1408
1554
1427
1403
1406
1401

1396
1430
1438
1418
1411
1414



Only two geomagnetic storms were reported during the interval. Figures 2a through 7b are a
compilation of magnetic records from sets of high and low latitude stations which show the develop-
ment of the two storms; unfortunately, Siberian data were not available at the date of writing.

The first geomagnetic storm began with a small ssc at 0916 UT on November 16. The ssc was
followed by a number of complicated worldwide geomagnetic disturbances. Thus, it is inferred that
the solar wind flow behind the shock wave, which passed near the earth at 0916 UT, was quite "tur-
bulent" or "structured", The "turbulent" flow lasted until about 07 UT on November 17 [ Yoshida
and Akasofu, 1966]. It is interesting to note that it is this period when the flux of the galactic
cosmic rays decreased by an amount of about 7%.

Flares 1 through 6 are unlikely to be the cause of the disturbed period of November 16/18;
they were of minor importance and the transit times for their particles were improbably long.
Flare 10 of the region M9772 was of sufficient intensity and its particles had enough transit time
to have caused the ssc and storm of November 16/18; however, Flares 7, 8, 9 and 11 cannot entirely
be excluded as the cause of the ssc while Flares 7, 8, 9, 11, 12 and 13 cannot be excluded as the
cause of the main phase decrease.

As mentioned previously, the initial part of the November 16/18 geomagnetic storm was very
complex. At low latitudes a number of si were observed and at both high and low latitudes, large
micropulsations were in evidence. Although Flare 10 probably caused the ssc of November 16 and
possibly the si that followed, some of the si during the initial phase may have been caused by
Flares 7 through 9 and 11 through 13. The observed Forbush decrease and plasma cloud transit time
to sse were more or less characteristic of a far eastern flare [Akasofu and Yoshida, 1967; Haur-
witz, et al., 1965], which is further confirmation that Flare 10 was responsible for the storm of
November 16/18.

HONOLULU

KAKIOKA

TANGERANG

TASHKENT

| 20»

M'BOUR

SAN JUAN

L i i 1 1 1 i 1 1 i 1 1 J
00 02 O04 O6 08 ite} 12 14 16 18 20 22 24
16 NOV 1968, HOURS, UT

Fig. 2a, H-component magnetic records of six low latitude stations for
November 16, 1968.

95



2 BL
S Se
08 oth og To t+— TT
a ROTATION 1851 7
|. \ PROTONS 5-21 MeV 7
10° [> 4
= - \ N _
A, 10? f- f a
8 C J 4
: |
& i |
% Wk \he a
Ss = za
- \ 4
Ie q
-}—— }- BACKGROUND 44 q
104 —p— $$ ttt to tt ——
|- ROTATION 1851 4
- PROTONS 21-70 MeV J
109 I +
T ioe \ a
ov [- 7
& - 4
Te 10 a
TE oe a
on f | BACKGROUND 4 q
- DAY NUMBER, 1968 -
jo7! FA Ps Wane ee Os
316 320 324 328 332 336 340 344

Fig. 1. ATS-1 Energetic proton flux November 11 - December 8, 1968.

33



"An Outstanding mm-Radioburst Observed November 18, 1968"

by
G. Feix
Astronomical Institute of University of Bochum, G.F.R.

(Permission has been given by the author and the publisher to use portions of the

article "Solar Bursts at Millimeter Wavelengths", J. Geophys. R., 75, 211-218, 1970.]

The author submitted Figure 1 which shows an outstanding limb flare-burst event.

The time of maximum was 1031 UT reaching an intensity of 5000 x 10-?2Wm-?uz7?.

The

observations at 36 GHz were made at the Stockert Radio Observatory (N50°34'14") by an

equatorially mounted paraboloid antenna 10 m in diameter.

The following paragraphs,

as well as Tables 1 and 2 are reproduced from the quoted article:

3. Spectra

Violent outbursts that are associated with a
flare event have been chosen for a special con-
sideration and are listed in Tables 1 and 2. The
observed radio spectrum of these events is given
in Figure 3. In comparing the spectra of limb
bursts and of selected strong disk bursts (Fig-
ure 4) there appears to be an unusual increase
of intensity at the mm-wavelength region for
limb bursts. This comparison is, of course,
restricted’ only to a small number of identified
limb sources. A comparison between the spectral
curves of Figure 3 and those of disk bursts
originating from the same plage indieate this
trend even more. Table 3 shows a few bursts
produced by the McMath plage No, 8740, whose
active center was identical with the source of
the limb event ESSA No. 4771 of Table 1, If
these events are considered to be typical for
this center of activity, we should find values of
8-13 X 10 W/m’ Hz for all bursts originating
from plage No. 8740 on the disk. Continuing
these investigations to the plages 9760 and
9503 of Table 1, one would obtain the same
results.

For example, (1) The active center of the
event described on July 6 became visible July 7,
1968. After July 6 no outstanding event was
detectable at 36 GHz from this plage. At the
time of the central meridian passage, as shown
by Figure 5, on July 12, 1968, the solar drift
curve represents the radiation of a common
plage during its passage across the disk. (2)
The limb burst of April 1, 1967, as shown in
Figure 2 has a radio output of about 4000 flux
units; this plage exhibited only events with flux
units lower than 100 x 10°? W/m* Hz at 36
GHz during its passage across the disk.

If this trend is substantiated it may prove
that the line of sight may play an important
role for the reception of microwave bursts,

yy
WAM tHe

sce
aa
tesa

wow of 30s me 2
ou

eso

Fig. 3. Power spectra of limb bursts at micto-
wavelengths, Data: Radio and Space Research
Station, Ditton Park, Slough, England; Solar-
Geophysical Data, ESSA, Boulder, Colorado;
Stockert Radio Observatory, Bonn, Germany.
Addenda: HHI, Berlin, Germany, received No-
vember 18, 1968: At 1027 UT, 94 GHz, maximum
flux units were 2600; at 1030 UT, 15 GHz, maxi-
mum flux units were 1090,

TABLE 1. Limb-Flare Characteristic
Optically _ Estimated
Central Observed Flux Units at ESSA
McMath Distance Area, 36GHz, Flare
Date Position Plage No. Maximum Maximum 10-"W/miHz No. Remarks*
April 1, 1967 N19-21 740 0.992 120 40004771 A; H
July 6,1968 N12-23; E85 503 1.000 220 24000 16373 A; Hj X
Nov. 18, 1968 N2i-23; W85-90 760 0.999 310 6500 A

* A = Eruptive prominence, base at > 90°.
H = Flare with high velocity dark surge.
X = Unusually wide H-alpha emission.

17



Counts in Minutes x 10°

54.0

52.0

50.0

Victoria Superneutron Monitor
Physics Department, University of Victoria,
Victoria, B.C., Canada
48° 25'N 123 W, Altitude 71 Meters
Barometric Constant (1964) 99.00 MM HG

:_ Five Minute Intervals

Pressure Corrected
ot

6.0

12.0 18.0
Universal Time (hours)

Fig. | November [8, 1968

6I

24.0





Table 2
FLARE APPROXIMATE LATITUDE
NUMBER DATE: 1968 __ START UT PLAGE REGION & MERIDIAN DISTANCE IMPORTANCE
1 November 13 0015 M9760 N18, W15 13
2 November 13 0910 M9772 N24, E90 1B
3 November 13 1103 49760 N19, W22 1B
4 November 13 1248 49760 N19, W21 1B
5 November 13 1411 M9772 N18, E82 1B
6 November 13 1716 M9760 N17, W28 In
7 November 14 2038 M9772 N13, E65 iF
8 November 14 2148 49760 N19, W45 iF
9 November 14 2254 M9772 N14, E66 iF
10 November 15 1030 49772 N14, E60 1B
sa November 15 1520 69768 N10, KOS 1B
12 November 16 0033 M9760 W17, W65 1N
13 November 16 0127 M9772 N13, E52 iF
14 November 16 2154 M9760 N16, W6S IN
15 November 16 2359 49760 N20, W67 iN
16 November 17 0103 69760 N17, W67 1s
7 November 17 0244 — M9760 N13, W67 1»
18 November 17 0707 M9772 N1O, E35 1B
19 November 18 0747 N9772 wll, £19 1F
20 November 18 1026 M9760 N20, W90 1B
21 November 18 1504 M9772 N11, #15 1F
22 November 19 0141 49780 317, E85 in
23 November 20 0118 M9780 $18, E60 in
24 November 20 0925 M9780 S24, E57 1B
25 November 20 1215 M9780 $20, E55 iN
26 November 20 1956 9780 S17, B58 1N
27 November 21 0031 M9772 N14, W18 1B
The consensus of solar observatories is that all the flares during the period November 13-21,
1968 associated with the above mentioned plage regions were of Importance i however, two of the
flares were reported to be of Importance 2 by one of the observatories in each case. They are
listed as 10 and 20 in Table 2. These flares may be responsible for the geomagnetic storms o:
November 16/18 and 20/21.
i - Julu, the probable interval of
Figure 1 illustrates the H-component magnetic record of Hono’ > (Pr .
arrival of flare particles for the flares listed in Table 2, and the ideneifiable si during the
period November 16-21, 1968. The numbers from 1 through 27 for the flares are t! le ‘same a8 in
enumeration scheme of Table 2. The dashed portion represents the first 20 hours a sex are ]
was sighted; the solid portion represents the next 52 hours. The interval of 20-72 hours from
93 i



Plotted in Figure 5 is each 9.28 second average proton flux measured in five proton energy
channels for a three hour interval around the sudden commencement. Clearly observed in the two
lowest energy proton fluxes is a sharp, approximately one minute wide peak at the time of the sud-
den commencement. This peak is not observed in the higher energy fluxes. Inmediately following
the sudden commencement, a decrease of the proton fluxes is observed in all proton energy channels.

Although a similar narrow enhancement at the time of the sudden commencement was observed in
the lowest energy alpha channel, no enhancement was observed in the electron fluxes. The data of
Figure 4 indicates clearly that the electron fluxes appear to decrease prior to the sudden commence-
ment and then to increase in intensity after the interplanetary disturbance has passed.

106 -—7—t —— J
E SC 4
L y At J
S108 0.56-0.60 Mey |
eae eee
L 4
. E- 10°
[ A2 7
L A 0,6-1.2 Mev -
T ee Ne L
> ? — a
3 E 5 10° 3
5 L AZ d s
B al 1.2-2.4 Mev °
© [0 F aan 10°] 9
® ben eve—sornens [~~ J o
om &
a_ Ny
E r 7 Fi
~ oe 4 r
gf { 2
eg Dt ec
° b 4 °
& L 44-soMev | 3 &
Pet te
L | oa
3h
108 b 107
C D2 7
L 5.0-9.4 Mev |
[eerie pram
S10? Rate ieeececene
to! 1 1 n 1 1 L
08 09 10

HOUR, NOVEMBER 20, 1968, UT

Fig. 5. High time resolution proton data measured during the time of the sudden
commencement at 0904 UT, 20 November. Each data point corresponds to a

9.28 second counting average.
38



KAKIOKA
TANGERANG
[sy
TASHKENT
M'BOUR ae
SAN JUAN

L 1 _L 1 1 1 1 1 1 1 4 1 J
00 02 O04 O6 O8 ile} 2 14 16 18 20 22 24
20 NOV 1968, HOURS, UT

Fig. 6a. H-component magnetic records of six low latitude stations for
November 20, 1968.

COLLEGE

5007
L

SODANKYLA

LEIRVOGUR LAG aime

GREAT WHALE

RIVER a | te nes
MEANOOK NN

L L 1 L 1 1 1 1 L L i 1 J
oo 02 04 06 O8 10 12 14 16 18 20 22 24

20 NOV 1968, HOURS, UT
Fig. 6b. H-component magnetic records of five high latitude stations for
November 20, 1968.

100



NV

0 ie) i 0
ty IR el a eI om
aad Ma " “rH
n E .. ; . ceee o, C88 LL 02
009 ~
4 peta Ltn h ON tL 0
i Qe = wre ol
0 ——-
n Ha ce gee tee . ASL. oz
009 7 ts
; AON Ol, 18) 3
> > — an SLIOAITIW NI 7
FANLITWY TVILNaLOd 19;
ANVvadvoud JHL SI ¢
o——t D4S/W> NI ALIDOTIA 4
A E | GNIM &VIOS NW3d 3HL SIn soz
009 ——=" OS8L

6961

“y NV&-896L ‘8 AON *6 Y3INOld

6

41