STUOT OF

(ST1P) WORKSHOP TRAVEL

FINAL REPORT

NAGW-743

Submitted to

HeadquarterS

Washington, DC 20546

S. T.

University of

{NASa-CE-17651|4) STUDY OF TRAVELLING N86-21477

INTSBPLANETaBY PBENOMESA (STIP). WORKSHOP

TBAVEL Final Bcpcrt (Alabama Deiv.r .

Huntsville.) t6- p flC A03/HF A01 CSCL 03B Onclas

63/90 05539

January 1986
This grant supported six American scientist participation at the

SCOSTEP/STIP Symposium on Retrospective Analyses and Future Coordinated

Intervals held at Le Diablerets, Switzerland on June 10 - 12, 1985.

Without this support the American participation would have been decreased. A strong tie among the international scientists working on

retrospective analyses and future coordinated intervals was developed. A

proceedings of the workshop will be completed and published within the

year. A copy of the book of abstracts is included in the appendix. The

American Scientists supported by this grant delivered six papers. The

titles are as follows:

1. An Analysis of Near-Surface and Coronal Activity During STIP

Inverval XII, Dr. Thomas E. Gergely, Astronomy Program, University of Maryland, College Park, MD 20742

2. Helios Images of STIP Intervals VI, B. V. Jackson, Department of

Electrical Engineering/Computer Science, University of

California, San Diego, La Jolla, CA 92093.

3. Results from the Analysis of Solar and Interplanetary Observations During STIP Interval No. VII, August - September 1979, S.

R. Kane, Space Science Laboratory, University of California at

Berkeley, Berkeley, CA 94720.

4. STIP Interval XIV, 20 May to 20 July 1982, E. Cliver and S.

Kahler, AFGL/PHG, Hanscom Air Force Base, Bedford, MA 01731.

5. Hydrpmagnetic Buoyancy Force in the Solar Atmosphere, T. Yeh,

University of Colorado, Boulder, CO 80309.

6. A Combined MHD Modes for the Energy and Momentum Transport From

Solar Surface to Interplanetary Space, S. T. Wu, Department of

Mechanical Engineering, The University of Alabama in Huntsville,

Huntsville, AL 35899.

It is our strong belief that NASA's support for this kind of international activity is necessary so that our scientific community is not

isolated to support our continued work with the broadest possible

spectrum.
STIP SYMPOSIUM

ON RETROSPECTIVE ANALYSES

AND FUTURE COORDINATED INTERVALS

BOOK OF ABSTRACTS

Les Dleblerets, Switzerlan d

10-12 June 1985

Sponsore d by SCOSTEP, COSPAR , IAU and IUPAP
SCIENTIFIC PROGRAM COMMITTEE:

A. Hewish

T. Combos!

Y. Leblanc

D. F. Smart

M. Dryer, Chairman

R. T. Stewart

T. Watanabe

K.-P. Wenzel

S. T. Wu

G. N. Zastenker

LIST OF STIP INTERVALS:

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

STIP

.STIP.

STIP"

STIP

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

Interval

^Interval

'Interval

Interval

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

I - S.

II - 1!

Ill - l:

IV - 1

V - Ji

VI - 1.

VII -: Al

VIII - 1

IX - 1!

X -2 1

XI - Oi

XII - 11

XIII - 1

XIV - 21

xv - i:

XVI - 2'

XVI H - .^ Si

X-VWf - ' M<

VII

September - October 1975

15 March - 15 May 1976

15 March - 15 May 1977

15 October - 15 December 1977

June - July 1978

15 April - 15 June 1979

August - September 1979

15 October - 15 December 1979

15 February - 16 March 1980

26 April - 27 June 1980

October - November 1980

10 April - 21 June 1981

1 December 1981 - 31 January 1982

20 May - 20 July 1982

12-21 February 1984

24 - 30 April 1984

Sefxtembe.r 1985 (Comet Giacobini-Zinner)

March 1986 (Comet Halley)

If- Jit
STIP SYMPOSIUM ON RETROSPECTIVE ANALYSES AND

FUTURE COORDINATED INTERVALS

June 10 - 12, 1985.

Les Diablerets, Switzerland

Sponsored by

SCOSTEP, COSPAR, IUPAP, and IAU

TENTATIVE PROGRAM

Monday, June 10, 1985 [AM]

0830 - 0930: REGISTRATION [Please provide 75 dollar Registration Fee in

U.S. $. Gala Banquet and Proceedings Volume are included.]

0930 - 0940: WELCOMING REMARKS (M. Dryer)

SESSION 1 (Chairman: M. Dryer)

0940 - 1005: "OVERVIEW OF STIP INTERVALS I - XIV." (M.A. Shea and

M. Dryer). [Invited]

1005 - 1030: Coffee.

1030 - 1100: "SCIENTIFIC RESULTS OBTAINED DURING STIP INTERVALS I AND II."

(M.A. Shea and D.F. Smart). [Invited] &e*;-,^.^| l

1100-1120 : "A REVIEW OF DISTINCTIVE FEATURES OF THE COSMIC RAY NEUTRON

INTENSITIES DURING THE RETROSPECTIVE WORLD INTERVAL II."

(H. Takahashi, T. Chiba, and N. Yahagi).

1120 - 1150: "STUDY OF INTERPLANETARY PROPAGATING PHENOMENA DURING THE

.

 STIP

 INTERVALS III AND IV." (J.-K. Chao). [Invited]

\1150 - 1210: "INTERPLANETARY FLARE-GENERATED OBLIMAKS." (K.G. Ivanov,

' A.F. Harshiladze, N.V. Mikerina, and P.P. Pavlov).

1210 - 1240: "STUDY OF INTERPLANETARY SPATIAL STRUCTURES DURING STIP

INTERVAL V (June-July 1978)." (R. Gold and D. Venkatesan).

[Invited]

1240 - 1300: "PERSISTENCE OF SOLAR WIND FEATURES." (H.O. Rucker,

M.D. Desch, and G.K. Rabl).

1cti_\cii.->.v v^t>--»_\ V..i\.., u^<kV. .

1300 - 1'IQO: LUNCH.
MONDAY, JUNE 10, 1985 [PM]

SESSION 2 (Chairman: T. Watanabe)

1400 - 1130:

1130 - 1500:

1500 - 1530:

1530

1600

1600:

1630:

1630 - 1700:

1730

1800

2000

1800:

2000:

2100:

"STIP INTERVAL VI: 15 April - 15 June 1979." (B.V. Jackson)

[Invited]

"RESULTS FROM THE ANALYSIS OF SOLAR AND INTERPLANETARY

OBSERVATIONS DURING STIP INTERVAL NO. VII, AUGUST - SEPTEMBER

1979." (S.R. Kane). [Invited]

"SOLAR, INTERPLANETARY AND GEOMAGNETIC DISTURBANCES DURING

STIP INTERVAL VIII." (C.S. Wright and R.J. Thompson).

[Invited]

Coffee.

"IPS AND SPACECRAFT OBSERVATIONS RELEVANT TO STIP INTERVAL IX

(Feb. 15 - Mar. 15, 1980). (T. Watanabe and A. Barnes).

[Invited]

"A SUMMARY OF THE SCIENTIFIC PROGRESS GAINED FROM THE STUDY

OF STIP INTERVAL X (26 April - 30 June 1980)."

(R.A. Harrison). [Invited]

(Title to be Supplied) (J.-L. Bougeret). [Invited]

DINNER.

OPEN BUSINESS MEETING

TUESDAY, JUNE 11, 1985 [AM]

SESSION 3 (Chairman: D.F. Smart)

0900 - 0930:

0930 - 0950:

0950 - 1010:

1010 - 1030:

"AN ANALYSIS OF NEAR-SURFACE AND CORONAL ACTIVITY DURING STIP

INTERVAL XII." (T.E. Gergely). [Invited]

"INTERPLANETARY SHOCK WAVES: NEW RESULTS ON SOLAR WINf;

OBSERVATIONS DURING STIP INTERVAL XII. (G.N. Zastenker ar-:J

N.L. Borodkova).

"ENERGETIC PARTICLE EVENTS DURING STIP INTERVAL XII."

(B. Sanahuja).

"IPS AND SPACECRAFT OBSERVATIONS OF THE INTERPLANETARY

DISTURBANCES DURING MAY 1981 IN STIP INTERVAL XII."

(T. Watanabe, T. Kakinuma, and M. Kojima).

1030 - 1050: Coffee.
1050 - 1120: "SOLAR VARIATIONS AND RELATED INTERPLANETARY FIELD AND

PARTICLE BEHAVIOR OBSERVED DURING STIP INTERVAL XIII.

(H.A. Taylor). [Invited]

1120 - 1140: "AN EXAMPLE OF RELATED SOLAR PERTURBATIONS OBSERVED AT EARTH

AND VENUS DURING STIP INTERVAL XIII." (H.A. Taylor)

/ Cv'< i~i/1<^ F<UI .-

11110 - 1210: "STIP INTERVAL XIV, 20 MAY TO 20 JULY 1982." (E. Cliver and

S. Kahler). [Invited]

' - - ;

1210 - 1400: LUNCH.

TUESDAY, JUNE 11 , 1985 [PM]

SESSION 4 (Chairman: S. Pinter)

1400 - 1430: "STATUS OF THE INTERNATIONAL HALLEY WATCH (IHW)."

(R.L. Newburn, Jr. and J. Rahe).. [Invited] [

1'130 - 1500: "THE LARGE-SCALE PHENOMENA NETWORK OF THE INTERNATIONAL j

HALLEY WATCH (IHW)." (J.C. Brandt, M.B. Niedner, and i

J. Rahe). [Invited]

 J

1500 - 1520: "SOFT X-RAY BURSTS ASSOCIATED WITH CORONAL MASS EJECTION

ONSETS." (R.A. Harrison and G.M. Simnett).

1520 - 15*10: "THE INITIAL FLARE DISTURBANCE." (D.S. Spicer)

1540 - 1600: Coffee.

1600 ~ 1620: "HYDROMAGNETIC BUOYANCY FORCE IN THE SOLAR ATMOSPHERE."

(T. Yen).

1620 - 1640: "RELATIONSHIP BETWEEN U-BURSTS, TYPE II BURSTS AND CORONAL

TRANSIENTS." (Y. Leblanc).

1640 - 1700: "COMMENTS ON SHOCK WAVES GENERATED BY SOLAR FLARES."

(A. Maxwell).

C-Cr-.Q/vi-D

1700 - 1720: "A—HYBRID MHD MODELS FOR THE ENERGY AND MOMENTUM TRANSPORT

FROM SOLAR SURFACE TO INTERPLANETARY SPACE." (S. T. Wu).

-1720— 1740: "VOYA-6ER OBSERVATIONS-OF-LOVf-A'ND-HTGH- COSMIC RAY INTENSITY

DURING 1980." (D. Venkatesan. R.B. Decker and S.M. Krimigis).

1740 - 1800: "INTERPLANETARY SHOCK WAVES OBSERVED DURING APRIL 17, 1978

EXPERIMENT BY THE VOYAGER RADIO ASTRONOMY." (Y. Leblanc and

D.F. Smart).

/''V-/.,- j ,--

1830—-2030: GALA BANQUET ' ' ' '-'•• y c .

^CC 3
WEDNESDAY, JUNE 12, 1985 [AM]

SESSION 5 (Chairman: J.-K. Chao)

0900 - 0920:

0920 - 0940:

0910 - 1000:

1000 - 1020:

1020 - 1040:

.1040 - 1100:

1100 - 1120:

1120 - 1140:

1140 - 1400:

"INTERPLANETARY ACCELERATION AND CONFINEMENT OF LOW ENERGY

SOLAR PARTICLES BY THE FLARE PLASMA DISTURBANCE." (E.C.

Roelof, P. van Nes, R. Reinhard, T.R. Sanderson and

K.-P. Wenzel).

"VARIATION IN ELEMENTAL COMPOSITION OF SEVERAL MeV/NUCLEON

PARTICLES OBSERVED IN INTERPLANETARY SPACE." (R.E. McGuire,

T.T. von Rosenvinge, and D.V. Reames).

"A SIMULATION STUDY OF TWO MAJOR EVENTS IN THE HELIOSPHERE

DURING THE PRESENT SUNSPOT CYCLE." (S.-I. Akasofu,

Wei Sun, C. Fry, W. Fillius, and M. Dryer).

"A TRANSIENT, THREE-DIMENSIONAL MHD MODEL FOR NUMERICAL

SIMULATION OF INTERPLANETARY DISTURBANCES." (S.M. Han,

S.T. Wu, and M. Dryer).

Coffee.

"PRELIMINARY SUMMARY OF THE OBSERVATIONS MADE DURING STIP

INTERVAL NO. XV, 12-21 FEBRUARY 1984." (S.R. Kane).

"UNUSUAL RECURRENCY OF ERUPTIVE PROMINENCES OF 20 APRIL

1984." (B. Rompolt). liy^A L»-/ p. ^-i-tv / 0 ,-u e^

"THE VARIABLE NATURE OF THE SOLAR WIND INTERACTION WITH COMET

HALLEY AS IT APPROACHES THE SUN." (K.F. Flammer,

D.A. Mendis, and H.L.F. Houpis)

LUNCH. Bur '.-..-ccu_

WEDNESDAY, JUNE 12, 1935 [PM]

SESSION 6 (Chairman: K.G. Ivanov)

1400 - 1420:

1420 - 1440:

144C - 1500:

"THE INTERNATIONAL COMETARY EXPLORER MISSION."

(J.C. Brandt)

"ELECTROSTATIC POTENTIAL BARRIER AT THE INTERPLANETARY SHOCK

FRONT ACCORDING TO SOLAR WIND MEASUREMENTS ONBOARD THE /•/

"PROGNOZ-7,8" SATELLITES-11—(-H^-br-Borodkova and -

G.M. Zastenker).

\

"EMPIRICAL TECHNIQUE FOR PREDICTING TIMES-OF-ARRIVAL OF

SHOCKS FROM POWERFUL FLARES." (S. Pinter and M. Dryer).
1500 - 1520: "INTERPLANETARY SHOCK WAVE INTERACTIONS AND THE RESULTING

ENERGY CHANGES DURING STIP INTERVALS." (S.A. Crib) UJ-.»(X A V

"f^i'i •-^•-\ iw\- £i,3.i~iii V^:_T- t n ix/ (>,-u !- -r-- f

1520 - 1510: Coffee. ' ' ' £' ^ ' '

' ? *'^a '• "d^\f~

15/10 - 1600: "HKLIOS IMAGES OF STIP INTERVAL VI: APRIL 15 - JUNK 15,

1979." (B.V. Jackson). \ocv.-ct .

1600 - 1620: "OBSERVATIONS OF THE QUIET SUN AT DECAMETER WAVELENGTHS."

(Ch. V. Sastry)

T52Q - 1630: "GLOBAL STRUCTURE OF THE SOLAR CORONA DURING STIP

INTERVAL VI" (R. A. Howard, M.J. Koomen, D.J. Michels,

and N. R. Sheeley, Jr.)

1630 - 1650 "ACCELERATION OF CORONAL MASS EJECTIONS AT LARGE HELIOCENTRIC

DISTANCES." (D.J. Michels, R.A. Howard, M. J. Koomen, and

N.R. Sheeley, Jr.)

1650 - 1710 "THE GREAT SOLAR FLARE OF APRIL 24, 1985, AND ITS EFFECT ON

INTERPLANETARY SCINTILLATION." (R. V. Bhonsle et al.)

1710 - Late Abstracts

Closing Session
OVERVIEW OF STIP INTERVALS I-XIV

M. A. Shea

Air Force Geophysics Laboratory

Bedford, Massachusetts 01731, U.S.A.

M. Dryer

Space Environment Laboratory

NOAA, Boulder, Colorado, U.S.A.

ABSTRACT

During the past ten years special periods of time have been established

by the Study of Travelling Interplanetary Phenomena (STIP) scientific study

group' for the study of solar and interplanetary phenomena. Designated as

STIP INTERVALS, these periods, most of which have been approximately two months

in length, were either designated in advance, in anticipation of planned spacecraft

configurations, or selected retrospectively, in an effort to have concentrated

studies of specific solar-initiated activity. In this overview we present the

historical background of these STIP Intervals and a summary of the rationale

in the selection of the first 14 intervals.
SCIENTIFIC RESULTS OBTAINED DURING STIP INTERVALS I AND II

M. A. Shea and D. F. Smart

Air Force Geophysics Laboratory

Hanscom AFB, Bedford, Massachusetts 01731, U.S.A.

ABSTRACT

A summary is presented of the scientific results obtained during studies

of solar and interplanetary phenomena that occurred during STIP Interval I

(September-October 1975) and STIP Interval II (15 March - 15 May 1976).

Although both of these time periods were within a year of the solar minimum

between the 20th and 21st solar cycles, the periods were extremely different

in terms of solar activity and related interplanetary phenomena. STIP

Interval I was characterised by a sparsity of significant solar activity as

typical of solar minimum conditions, whereas STIP Interval II was more typical

of conditions closer to solar maximum. This unexpected solar activity during

solar minimum included several flares of importance 1, solar-initiated

interplanetary shock waves with detection at 9.7 AU, and a relativistic solar

particle event detected at the earth. The configuration of spacecraft from 0.3

to 9.7 AU and at different heliospheric longitudes throughout the solar system

enabled unique measurements of these phenomena.
A REVIEW OF DISTINCTIVE FEATURES OF THE COSMIC RAY NEUTRON

INTENSITIES DURING STIP INTERVAL II

Takahashi, H., T. Chiba, and N. Yahagi

Department of Physics, Iwate University

Mori oka 020, Japan

ABSTRACT

The followin g distinctiv e feature s on the cosmic ray neutron intensity

variations have been observed durin g STIP Interva l II, 20 Marc h - 1^ May ,

1976:

(1) The storm-time increase due to the rin g current effects on cosmic

rays on 26 March and 1 April, 1976, respectively.

(?) Tne solar cosmi c ray increase on 30 April , 1976. This phenomenon

was not observed at the stations in Japan.

(3) The three consecutive Forbush decreases started on 25 .March, 29

March, and 1 April , 1976

CO Intensity decreases started on =11 April , 1976.

The mechanism s and discussion s of thes e feature s as well as the

associated phenomena will be reviewed and discussed together wit h our results

concerning these features.
STUDY OF INTERPLANETARY PROPAGATING PHKNOMKNA

DURING STIP INTERVALS III AND IV

Jih K. Chao

Department of Atmospheric Physics

Nationa l Central University

Chung-Li, Taiwan 320

R. 0. C.

A review of some of the results of interplanetary propagating phenomena

for the periods from 1.5 March - 15 May and 15 October - 15 December, 1977 is

<riven . Especiall y the shock events of November 22 - December 6, 1977 will be

discussed in detail. Based on these and some other observationa l results a

mode l for the propagatio n of a solar flare- or CME (Coronal Mass Fijection)-

associated interplanetar y shock wav e is given . A physica l mechanis m is

describe d to calculat e the probabilit y that a weak shock whic h enters a

turbulent solar wind region wil l degenerat e into a M.MD wave . That is, the

shoc k woul d disappea r a s an entropy-generatin g entity . This mode l also

suggests that most interplanetary shock waves cannot propagat e continuousl y

wit h a smoot h shoc k surface . It is suggeste d that the surfac e of an

interplanetary shock will be highl y distorted and that parts of the shock

surfac e can degenerat e into MHD waves or even disappea r durin g its global

propagation through interplanetary space. A few observations to support this

model will be briefly described.

Finally , this model of shock propagation also applie s to corotatin g

shocks. As corotating shocks propagate into fluctuatin g ambien t solar win d

regions, shocks may degenerate into waves or disappear.
INTERPLANETARY FLARE-GFNERATED 03LIMAKS

K.G. Ivanov, A.F. Harshiladze, N.V. Mikerina, and

P.P. Pavlov

Institute of Terrestrial Magnetism,

Ionosphere and Radio Wave Propagation

Of the Academy of Sciences

Troitsk, Moscow Region

1^2092, USSR

It is suppose d tha t an interplanetar y hydromagne t ic cloud can be

considered as an flare-generated oblate spheroma k or "oblimak " wit h a

predominantl y force-free magneti c field . The magnetic field of the oblirnak

can be approximately described by

8 = n x Vf + 7 V x (r, x VY) ,

K

where Y = £Eamn Vmn, the double set of the spheroidal wave functions.

In a low approximation

a fl nccoscn + sincn

=

 A00 ~c!T " 01 2~2 *"

c n

wher e n and C are the spheroida l coordinates; c is a constant. These

theoretical considerations have been applied to the hydromagneti c cloud from

the' isolated solar flar e on 22 Novembe r 1977 (STIP Interval IV) Under some

conditions a satisfactory agreement between the theory and the observation s

has been achieved.

10
STUDY OF INTERPLANETARY SPATIAL STRUCTURES DURING

STIP INTERVAL V (JUNE-JULY 1978)

R. E. Gold1 and D. Venkatesan1'

2

The Johns Hopkins University

Applied Physics Laboratory

Laurel, Maryland, 20707, USA

9

The University of Calgary

Calgary, Alberta, T2N 1N4, Canada

ABSTRACT

STIP Interval V, June-July 1978, is an unusually interesting

period. The interval is within the fast rising portion of sunspot cycle 21

and it is rich in solar flare effects. However, direct propagation of flare

particles is observed near-earth only in May and August 1978, flanking the

interval of study. During STIP interval V we observe several well formed

interplanetary structures sweeping past the earth. Numerous low energy

particle increases are observed as well as four Forbush decreases in groundbased neutron monitors. This paper will discuss the various interplanetary

spatial structures using ion and electron data from the IMP spacecraft nearearth in the energy range of 0.2 to 500 MeV, complemented by data from

Voyagers 1 and 2 at ~ 3.5 AU and separated from earth by ~ 180° of heliolongitude.
PERSISTENCE: OF SOLAR WIND FEATURES

H.O. (tucker'^, M.D. Desoh'0), and C.K.

') Space Research Institute, Austrian Academy of Sciences,

Observatory Lustbuehel, A-80U2 Graz, Austria.

2) NASA/GSrC, Laboratory for Extraterrestrial Physics,

GreenUelt, MD 20711, USA.

Using data from the plasma and magnetometer experiments of Voyagers 1 & 2

during the approach to Jupiter, the analysis covers the period from January

1978 (Voyage r 1 passing over Voyager 2) through February 1979. The

trajectories of both spacecraft provided a unique opportunity to study the

radial evolution and variation of the solar wind over about 3 AU, and to

analyse the persistence of solar wind features along the radially increasing

separation distance of both Voyagers.

Special emphasis is laid on a period of DOY (day of year) 166 through 210,

1978, in which the observed propagation delay time of solar wind signatures

between both Voyagers significantly deviates from the expected delay time. A

drop-down of the correlation coefficient of the corresponding Voyager 1 X 2

data profiles indicates a change from recurrent to nonrecurrent solar wind

flow. This period in question coincides to a great extent with STIP interval

V of June - July 1978.

12
STIP Interval VI: 15 April - 15 June, 1979

B. V. Jackson

University of California, San Diego, La Jolla, California 92093, U.S.A.

The analysis of STIP Interval VI generally involves several large coronal

mass ejections and interplanetary shocks which occurred during this time

period. In retrospect, this interval was significant because the first data

from the NRL coronagraph became available (on 28 March 1979) to be coordinated

with several well-placed spacecraft in situ and remote sensing measurements

within 1 AU of the Sun.

Examples of the interplanetary data include: 1) An event on 22-27 April

which gives evidence that a proton event and shock observed at Earth and by

the Venera 11 and 12 space probes was associated with a flare and filament

eruption near Sun center. 2) A coronal mass ejection on 8 May that can be

followed by in situ spacecraft observations up to and beyond the orbit of

Venus giving associated interactions with the Venusian atmosphere. 3) Two

mass ejections on 7 May and 24 May which appear to accelerate near the outer

edge of the NRL coronagraph field of view (near 10 RQ). They are observed

later in Helios white light photometer data over periods of several days as

they move outward from the Sun.

In addition, near solar surface analyses include several studies of

metric radio bursts and their comparison with solar surface features during

this interval.

1.3
RESULTS FROM THE ANALYSIS OF SOLAR AND INTERPLANETARY OBSERVATIONS

DURING STIP INTERVAL NO. VII, AUGUST - SEPTEMBER, 1979

S. R. Kane

Space Sciences Laboratory, University of California, Berkeley, California, USA

The solar activity during STIP Interval No. VII was characterized by several major flares such as those on August 14 (VL244 UT), August 18 (^1405 UT) and

August 21 (^0615 UT). The August 14 and 18 flares produced intense X-ray and radio emissions as well as energetic particles. On the other hand, the August 21

flare produced relatively weak X-ray and radio emissions but very energetic particles which were detected by ground level neutron monitors. These flares produced coronal transients and interplanetary shocks. Instruments aboard several

spacecraft and ground-based observatories were operating during STIP Interval

No. VII. Many aspects of the solar-interplanetary phenomena were therefore observed through in-situ measurements and/or remote sensing techniques. Analysis

of these measurements has led to theoretical studies such as numerical simulation and dynamical modeling. These studies are expected to help in the understanding of processes such as particle acceleration and generation and propagation of coronal shocks and interplanetary disturbances. A summary of such observational and theoretical studies will be presented.
SOLAR, INTERPLANETARY AND GEOMAGNETIC DISTURBANCES DURIviG

STIP INTERVAL VIII.

C.S. Wright and R.J. Thompson

Department of Science, Ionospheric Prediction Service

P.O. Box 702, Darlin^hurst, 2010, AUSTRALIA

ABSTRACT

Several major solar flares and filament disappearances, which were

comparatively well-observed, occurred during STIP Interval VIII, 15 Oct. 79 -

15 Dec. 79. Interdisciplinary observations include simultaneous gamma-ray,

x-ray, H-alpha and microwave measurements of flares; indirect (radio) and in

situ measurements of coronal and interplanetary shocks; coronagraph and

satellite occultation measurements of coronal transients, including what seems

to be the first reported 'head-on' observation of a white-light coronal

transient following a filament disappearance. In spite of the substantial

flare and filament activity , the geomagnetic field remained relatively

undisturbed.

An overvie w of the main observations and results is provided. The

results for individual coronal and interplanetary transient event s are

examined in the light of conclusions drawn from statistical studies of the

effects of flares and filament disappearance upon the geomagnetic field.

15
IPS and Spacecraft Observations Relevant to STIP Interval IX

(Feb. 15 - March 15, 1980)

coordinated by

Takashi Watanabe

Research Institute of Atmospherics, Nagoya University

Toyokawa 442, Japan

and

Aaron Barnes

Ames Research Center, NASA

Moffe t Field, California, U.S.A.

The solar-interplanetary events whic h took place around the STIP

Interval IX are discussed on the basis of the solar wind data obtained

wit h IPS observations and spacecrafts. At least three solar-flare

associated shock wave disturbances and two NCDF (non-compressive densit y

enhancement) events were observed near 1 AU heliocentric distance in the

interval from Feb. 12, 1980 to March 22, 1980. The NCDEs were observed

at Helios A on Marc h 18 and on March 22 respectively. The IPS

observations shows tha t the NCDEs wer e the expandin g shells of high

density plasma with the speed of 300-400 km s .

16
A SUMMARY OF THE SCIENTIFIC PROGRESS GAINED FRGi-i THE STUDY OF STIP INTERVAL X

(26 APRIL - 30 JUNE, 1930)

Richard A. Harrison

High Altitude Observatory

National Center For Atmospheric Research*

Boulder, Colorado, USA

ABSTRACT

A summar y is presented of progress made in the understanding of the solar

corona through studies of activity withi n STIP Interval X (26 April - 30 June ,

19BO). There were many notable and extremely fruitfu l features of this period.

For example, in late June solar activity was dominated by the limb crossing of

a vast complex of active regions whose recurrent flarin g was (a) ideally

placed for the correlation of solar surface and coronal activity , and was (b)

wel l suite d to studie s of homology and coronal recovery . Despit e flare -

activit y an d mass ejection , this comple x displaye d a remarkabl y stabl e

hierarch y of X-ra y emittin g coronal arches achieving altitudes of > 1.5 * 10^

km. Earlier in the Interval, on May 21-22, a similar X-ray emittin g arch was

seen afte r the eruptio n of a classical two-ribbo n flare . This arch was

located under a vast stationary post-flare noise storm and togethe r they are

though t to be signature s of a magneti c bottle extending beyond 1 Ro from the

limb . Fortuitious observational sequences made on June 29 and Apri l 27 have

allowe d detailed study into the relationships between coronal transients and

Type II and Type IVm radio bursts, respectively. There is evidence to suggest

that the Type II related disturbanc e is faste r than, but has. a later onset

time than, the transient, and it has been shown that the densit y in Typ e IVm

emittin g regions is high enough for plasma emission, a point that had been in

some doubt. Fo two periods withi n STIP Interva l X a surve y of the corona

above Type III producing regions has been performed, leading to the suggestion

that , in visibl e light , such a regio n characteristicall y ha s a comple x

structur e of small short-lived, dense blobs. Towards the end of the Interval,

on June 21, the first direct observation of solar neutrons was mad e at 1 A.U .

The boundarie s of this STIP Interva l have no physica l significance . The

scientifi c gains are varie d due to a large spectru m of activity , and are

mainl y due to an unusuall y rich data-set, primaril y because of the full y

operational Solar Maximum .Mission.

*The Nationa l Cente r for Atmospheri c Researc h is sponsored by the Nationa l

Science foundation.

17
Invited Paper by J.-L. Bougeret -

Title and Abstract Not Available

18
ORIGINAL

OF POOR

AM ANALYSIS OF NEAR-SURFACE AMD CORONAL ACTIVITY

DURING STIP INTERVAL XII

T.E. Gergely

Astronomy Program.

University of Maryland

College Park, MD 207'I2

STIP Interval XII which extended from April 10 to July 1, 1981 was

characterized by some of the largest flares of solar cycle 21. Most major

activit y took place in April and the first half of Hay, the second half of the

Interval was relatively quiet. A summary of the events that occurred during

this period was given by Gergely (1983)*. Although relatively recent, the

wealth of information acquired during this Interval already produced a large

number of analysis. Kost deal with the large flares that occurred on April 2^

and 27 and on May 8, 13 and 16. I review in this paper the progress made in

analyzing these events, with particular attention to the nature of the regions

where they originated from, and to their effects near the solar surface and

the inner corona. Many of these events produced large interplanetary

disturbances, which will be discussed elsewhere.

*Gercely, I.E.: 1983, Adv. Space Res., 2, 271.
INTERPLANETAR Y SHOCK WAVES: NEW RESULTS ON SOLAR WIN D

OBSERVATIONS DURIN G STIP INTERVAL XII

Zastenker G.N. , and Borodkova N.L.

Space Research Institute, Academy of Sciences

Moscow, USSR

Some new peculiar-tie s of the interplanetar y shock waves observed after

strong solar flares in April - June 1981 are described. Compariso n of energ y

release d by flares and measured later in the interplanetar y mediu.-n wit h

magnitude s of mean and local propagation velocities shows that the shock

velocit y is defined mostly by preceeding interplanetary conditions rather than

by flare energy. Observed shocks show rather low deceleration on the way fro m

the Sun to the Earth for a considerable number of events.

In the sequence of events observed afte r a series of stron g flare s

separated by no more than two days, the disturbanc e at the Earth's orbit

appeared as a monotonic and very strong increase of solar wind density withou t

detectabl e shocks. This can result from interaction of shocks durin g their

propagation from the Sun.

Calculatio n of the kineti c parameter jumps on the interplanetary shocks

from selective ion measurements shows that, in most cases, the velocit y of

a-particles increases less and the temperature of a-particles increase more

than those for protons. Estimation of potentia l jump s of shock fronts wit h

use of selective ion measurements suggests that the potential jump magnitude

depends on Mach number.

20
ORIGINAL P&QE 13

(DC POOR QUALITY

ENERGETIC PARTICLE EVENTS DURING STIF INTERVAL XII

BY

B. Sanahuja

Departamento de Fisica de la Tierra y del Cosmos, Universidad de Barcelona and

Grup d'Astrofisica de la Secci6 *de Ciencies del IEC. Barcelona, Spain.

ABSTRACT'

We present an analysis of several large particle events -mainly protonsobserved between 8 April and 26 June 1981, by near-Earth and interplanetary

spacecrafts. The most interesting proton events took place on April 10, 2'i

and 27 and May 8 and 1r,. They have been studied in detail considering their

association with interplanetary shocks, the solar activity that can trigger

each disturbance, and their propagation through the interplanetary medium.

Results will be also discussed in view of the current theories on particle

acceleration.

21
IPS and Spacecraft Observations of the Interplanetary Disturbances

During May 1981 in STIP Interval XII

Takashi Watanabe, Takakiyo Kakinuma, and Masayoshi Kojima

Research Instutute of Atmospherics, Nagoya University

Toyokawa 442, Japan

Three-dimensional propagation properties of the solar-flare

generated interplanetary disturbances observed in May 1981 are discussed

on the basis of IPS and spacecraft observations. On the interplanetary

disturbance associated with the solar flare of 2232 UT, May 8, 1981 (2B,

N09E38), the propagation speed at 1 AU heliocentric distance was similar

(500-600 km s~*) over the longitudinal range of 100° around the flare

normal. The interplanetary disturbance associated with the solar flare

of 0312 UT, May 13, 1981 (3B, N10E56) showed highly anisotropic

configuration; very high shock speed (1200 km s~ ) was obtained in the

region to the east of the flare normal. Similar configuration is seen

for the disturbance associated with the solar flare of 0824 UT, May 16,

1981 (3B, N11E16).

22
•VOL-A.=. VARIATION'S AND RELATED INTERPLANETARY FIELD AND PARTICLE BEHAVIOR

OBSERVED DURING STIP INTERVAL XIII

H.A. Taylor, Jr.

Laboratory for Planetary Atmospheres

NASA Coddard Space Flight Center

Greenbelt, Maryland 20771, USA

ABSTRACT

T he variabilit y of the Sun and related interplanetar y effects ar e

examinee for the STIP Interval XIII, which extends from Decembe r 1981 through

Februar y 1982. The solar variations exhibit relatively complex behavior wit h

a mixtur e o f activ e regions, flares, an d smal l scal e corona l hole s

interspersed across the interval. The coronal hole development during this

interva l is seen to be part of the preliminar y growth of the more extensiv e

hol e formation s observed later in 1982-1984. In this early stage, the coronal

holes ar e sufficientl y small and irregula r that the dominant , recurren t

pattern s of fiel d and particle modulations observed in the declining phase of

the prior solar cycle are not yet established. Nevertheless, the variou s

solar perturbation s are sufficiently unique and pronounced during this period

that correlated modulations of field and particle distribution s are observed

bot h withi n and beyond 1 AU. These observations indicat e an impressiv e

coherence sometimes present in the communicatio n of solar effects to widel y

differen t regions in the ecliptic plane. STIP Interval XIII is located withi n

the period identified by Fillius and Axfor d [1985] as a "false recovery" of

the sola r cycl e modulatio n in galacti c cosmic rays, and a s such offers

interesting possibilities for futur e investigations of both interplanetar y and

solarterrestial responses.

2:3
Ml EXAMPLE OF RKLATED SOLAR PERTURBATIONS OBSERVED AT F.ARTH AND VKNUli

DURING STIP INTERVAL XIII

H.A. Taylor, Jr.

Laboratory for Planetary Atmospheres

NASA Goddard Space Flight Center

Greenbelt, Maryland, 20771, USA

ABSTRACT

During the latter portion of STIP Interval XIII (December 1981-February

1982) Earth and Venus were nearly co-aligned with the Sun, permitting

comparisons of the environmental response at both planets for similar sola"

disturbances. During February 15-17, a high speed stream passed Venus and

F.arth with a separation of only a few hours. Usiny observations from

instruments on the Pioneer Venus Orbiter and on ISEE-3, the interplanetary

magnetic field and solar wind perturbations associated with this stream are

seen to be quite comparable at the two planets. At Venus, the response to the

stream passage is evident in the inward displacement of the bowshock and at

Earth the response is indicated in the expansion of the auroral oval

determined form observations on the Dynamics Explorer. In both locations, the

signature of the stream passage exhibits a rather complex time sequence of

enhancements in momentum flux and in IMF geometry. Such non-alignment of the

field and particle parameters in a high speed stream are not unusual and are

indicative of the complexit y involved in sorting out the mechanisms

responsible planetary responses.
STIP Interval XIV, 20 Hay — 20 July 1982

E. W. diver

Space Physics Division

Air Force Geophysics Laboratory

Hanscom AFB, MA 01731 USA

S. W. Kahler

Physics Research Division

Emmanuel College

Boston, MA 02115 USA

ABSTRACT

This interval is noteworthy for its high level of solar activity. Various

statistical studies of phenomena such as flare white.light emission, coronal mass

ejections, and interplanetary Type II bursts are based at least in part on events

observed during this interval. In addition, analyses have been made of the optical

and radio evolution of major active regions during this period and several flares

have been analyzed in detail. We focus on the solar aspects and interplanetary

effects of three major flares: 03 June, 06 June, and 12 July. The 03 June flare

provided the first case of a solar neutron event that was observed by ground based

neutron monitors and detected via decay neutrons in space. The 06 June event was

observed in X-rays, optically, and at radio wavelengths and exhibited well-defined

impulsive and gradual phases. Electrons above 20 keV deposited 1033 ergs in this

event, more than previously estimated for large flares. The 12 July flare had a

profound effect on the outer heliosphere. The Forbush decrease associated with

this event is clearly observed at Pioneer 11 at ~ 12 AU and, in two studies, this

event is tentatively linked with a later disturbance at Pioneer 10, ~ 28 AU from

the sun and ~ 150° in azimuth from Pioneer 11. The disturbance at Voyager 2 (near

pioneer 11) has been characterized as a magnetic cloud overtaking a corotating

interaction region.
STATUS OF THE INTERNATIONAL HALLEY V.'ATCH (IHl-;)

Ray L. Newburn, Jr.

Jet Propulsion Laboratory

Pasadena, CA 91109, USA

Juergen Rahe

Dr. Remeis Sternwarte

Bamberg, FRG

In the thre e years since Maynooth, Comet Halley has been recovered (Oct.

16, 1982), has developed a coma, and has begun to show emissio n line s in its

spectrum . Th e IHW ha s been formall y recognize d b y th e Interna t iorial

Astronomical Union and has developed eight observin g network s wit h over 900

astronomers in 4? countrie s as members. The nets held a trial run on Comet

Crommelin (Marc h 1981), and the Astrometry , Photometry , Spectroscopy, and

Infrare d Nets hav e obtaine d a larg e amoun t of usefu l data on Halley .

Meanwhil e IHW members recovered Comet Giacobini-Zinne r (Apr . 3, 1984) , and

coverage of this comet, whic h is the target of the ICE space craft on ilept.

11, 1985, has been added to that of Halley . The IHW and all cometary space

mission s ar e cooperating closely in every usefu l way . The Giotto , VEGA ,

Planet-A, and Astro 1 missions all have agreed to includ e their data in the

Halle y Archive , as has ICE (in a separate G-Z volume). We appreciate the

close cooperation of STIP as well in this growin g internationa l scientifi c

cooperation.

26
The Large-Scale Phenomena Network

of the International Halley Watch (IHW)

John C. Brandt, Malcolm B. Niedner

Laboratory for Astronomy and Solar Physics

NASA-Goddard Space Flight Center

and

JiJrgen Rahe

Remeis Observatory

The goal of the Large-Scale Phenomena Network is to obtain wide-band

visual wavelength photographs of Comets Halley and Giacobini-Zinner with

fields of view 2. 5° and on a nearly continuous basis during the periods of

cometary development or specific interest. A selected number of these images

will be fully processed, i.e., digitized and reduced to a standard magnitude

system. These efforts should naturally concentrate on spectacular events

occuring over an extended time period; an example is the disconnection event

or DE.

The network currently contains approximately 90 fixed observatory sites

with stated interest in participation. The distribution is not ideal in the

S. hemisphere and an "island network" was created to fill the gaps produced by

the Pacific, Atlantic and Indian Oceans. Two island sites have been

established for each ocean. Mobile observing teams will supply additional

coverage.

The first intensive use of the networks will be for Comet Giacobini-Zinner

and will serve as a dress rehearsal for Comet Halley. The intention is to

cover the comet for a 28-day period (one solar rotation) centered on the

intercept date of September 11, 1985. This corresponds to STIP interval

No. XVIII and clearly we expect a productive interaction.

The Halley's Comet activities are set for periods of general monitoring, '

geometrical alignments, and cometary activity. The most active period will be

March-April 1986. The March portion corresponds to the time of the Halley "

intercepts and is of prime importance. This corresponds to STIP interval

No. XIX. The triad of IHW, in situ, and STIP data should be very powerful. .

The kinds of STIP data believed to be useful for the cometary research •

will be briefly summarized.
Soft X-ray Bursts Associated With Coronal Mass Ejection Onsets

Richard A. Harrison

High Altitude Observatory

National Center For Atmospheric Research

Boulder, Colorado, USA.

and

George M. Simnett

Dept. of Space Research

University of Birmingham

Brimingham, U.K.

ABSTRACT: We present a summary of recent work which has shown that a weak, soft X-ray hurst, is a

signature of the coronal mass ejection onset phase. In many cases a flare follows the burst prompting us

to label it a precursor. These bursts commonly occupy much larger magnetic loop systems than the Hares,

even interconnecting active regions. We show that not only are the bursts temporally assoohiU-d with

ejection onsets but that their location, physical extent and morphology are remarkably consistent with

those of ejection.

* The National Center For Atmospheric Research is sponsored by the National Science Foundation.

28
THE INITIAL FLARE DISTURBANCE

BY

D.S. Spicer*

Astrophysics Division

NASA Headquarters

Washington, DC 205^6 USA

ABSTRACT

A brief Synopsis of the physical mechanism believed responsible for solar

flares will be presented. In particular, how each flare mechanism manifests

itself energetically will be reviewed, with particular emphasis on identifying

these mechanisms which can lead to a highly localized rapid energy release

and, thus, be construed as causing point explosions.

*0r. leave from the E.G. Hulburt Center for Space Research, U.S. Naval Research

Laboratory, Washington, DC 20375 USA.

29
BUOYANCY FORCE IN THE SOUR ATMOSPHERE

TYAN YEH

Cooperative Institute for Research in the Environmental Sciences

University of Colorado, Boulder, Colorado 80307

Abstract An extraneous magnetized body, either a magnetic rope or a

plasmoid, immersed in the solar atmosphere is subjected to a hydromagnetic

buoyancy force. It results from the peripheral inhomogeneity of ambient

hydromagnetic pressure, which is caused or enhanced by the presence of the

extraneous body. This extra-caused force acts at various mass elements of the

immersed body through its distribution as a nearly uniform force density, just

like the gravitational force. Since hydromagnetic buoyancy force comprises

hydrostatic buoyancy force, hydrodynamic lift force, and magnetostatic

diamagnetic force, this constitutes a magnetohydrodynamic generalization of

Archimedes' principle which deals with hydrostatic buoyancy force.

In the solar atmosphere hydromagnetic buoyancy force has an obliquely

upward direction, with a component in the direction opposite to the downward

gravity. It provides an upward force to counterbalance or even to exceed the

downward gravitational force. Such an upward force is the dynamic cause for

the stationary equilibrium of quiescent.prominences and outward motion of

coronal transients.

30
Relationship between U-bursts. Type II bursts and coronal transients

Yolande LtBLANC

Observatoire de Paris. Section de Meudon

LA CNRS 324

92195 Meudon Principal Cedex. France

ABSTRACT

Radio observations of U-bursts have provided Important Information on

loop transients and coronal structures. The results given In Leblanc and Hoyos

( 1985 ) and Leblanc et al. ( 1983 ) are discussed after two recent papers of

Sirr.e et al. (1984 ) and Cane ( 1984 ).

It is shown that the evolution of the electron density In loop transients

derived from radio observations is In agreement with that obtained from

coronograph observations, fha relationship between the occurrence of a Type

II burst and groups of U-bursts can be explained by the model proposed by

Cane where a coronal shock catches up a loop mass ejection. It Is suggested

that iho storm emission following generally the Type II burst Is located In tho

remaining legs of the loop transient.
STIP Meeting

Les Diablerets, Switzerland

10-12 June, 1985

ABSTRACT

COMMENTS ON SHOCK WAVES GENERATED BY SOLAR FLARES

Alan Maxwell

Harvard-Smithsonian Center for Astrophysics

Cambridge MA 02138, U.S.A.

Recent radio data on flare-generated shocks, both piston-driven and

blast-wave, are reviewed. Most of the shocks seem to have velocities

of the order of 750-1500'km s whilst they traverse the solar corona

but, for the most energetic flares, the velocities may range up to

about 3500 km s . Depending on the amount and duration of the energy

input at the flare site, the piston-driven shocks appear to propagate

at constant velocity out to 10-30 R and thereafter to continue as

decelerating blast waves. The relation of the shocks to optical

coronal transients is also examined.

32
A HYBRID MHD MODEL FOR THE ENERGY AND MOMENTUM

TRANSPORT FROM SOLAR SURFACE TO INTERPLANETARY SPACE

by

S. T. Wu

Department of Mechanical Engineering,

Univ. of Alabama in Huntsville

Huntsville, AL 35899, USA

ABSTRACT

A hybrid magnetohydrodynamic (MHD) model is suggested for

the study of the energy and momentum transport and its subsequent

propagation into interplanetary space. This hybrid model consists of four parts (i) by introducing a disturbance in the

photospheric level, then the amount of energy and momentum resulted from this disturbance can be determined. (ii) This

additional energy and momentum will cause heating, leading to

development of a pressure pulse through wave dissipation and

compression. (iii) This computed pressure pulse is then input

at the base of the corona (^20,000 km) producing a disturbance

that propagates through the coronal region. (iv) Finally, we

input the outer coronal results at 18RQ and, using our MHD code

(Wu et al. 1983), compute . the response in heliospheric space.

The reason for separating this problem into four different

parts, thereby forming a "hybrid" system is because there are

three different physical characteristics (i.e., spatial and time

scales) in these regions (photosphere/chromosphere, corona, and

interplanetary space). A numerical example is presented to illustrate this hybrid approach.

Wu, S. T., M. Dryer and S. M. Han, Solar Physics, 84,

(1983) 395-418.

Abstract submitted to the STIP Symposium on Retrospective

Analyses and Future Coordinated Intervals, Les Diablerets,

Switzerland, 10-12 June 1985.

33
VOYAGER OBSERVATIONS OF LOW AND HIGH COSMIC RAY INTENSITY

DURING 1980

D. Venkatesan1'

2, R. B. Decker2 and S. M. Krimigis2

The University of Calgary

Calgary, Alberta, T2N 1N4, Canada

o

The Johns Hopkins University

Applied Physics Laboratory

Laurel, Maryland, 20707, USA

ABSTRACT

The onset of the decline of the sunspot cycle 21 from its maximum

heg.in with 1980; during the sunspot maximum, solar polar coron.nl holes

retreated towards their minimal areas around the pole. Thus this epoch as

well as the beginning period of the sunspot decline are ideal intervals for

observing heliospheric phenomena not directly influenced by coronal holes.

Twenty-seven day recurrent structures were seen in the data of the two Voyager

spacecraft, during a period of relatively little solar flare activity. Some

of these features are absent in the data from the earth-orbiting spacecraft

IMP-8. A suggestion has been made in an earlier work from our group

(Venkatesan et al., 1984) that these may well arise from corotating interaction regions.

Data from the detectors onboard the Voyagers enable us to study the

following energy ranges: ~ 50-80 keV (Z > 1); ~ 0.5-1.4 MeV (Z = 1); ~ 4-10

MeV (Z = 1); 19 < E < 31 MeV; 3 < Ep < 17 MeV; Ep > 210 MeV; Eg > 2.5 MeV and

the M-scintillator (E > 35 MeV) onboard IMP-8. The differences are investigated in terms of forward and reverse shocks and corotating interaction

regions. The study reveals the complex nature of the interplanetary conditions during the year 1980.

34
INTERPLANETARY SHOCKWAVES

OBSERVED BY THE VOYAGER RADIO ASTRONOMY EXPERIMENT

DURING APRIL 1978

Yolande Leblanc

Observatoire de Paris

92195 Meudon Principal Cedex, France

D.F. Smart

Air Force Geophysics Laboratory

Hanscom AFB, Bedford, MA 01731, U.S.A

ABSTRACT

We analyzed the interplanetary shocks that were the source of five well

defined kilometric type II radio bursts observed in April 1978 by the

radio astronomy experiment (PRA) carried on the Voyager spacecraft.

The initia l speed of each of the shocks was determined from the observed

frequency drift rate. The results of this analysis show satisfactory

agreement with the hypothesis that the shocks were initially driven, and

then propagated as blast waves in the solar wind. We also deduce the

probable source location for the kilometric type II event observed by

the Voyager spacecraft on 17 April 1978 from the shock observations at

Helios 2, at 0.4 AU, Voyager at 2.9 AU, Pioneer 10 at 6.8 AU, and Pioneer

11 at 16 AU.
INTERPLANETARY ACCELERATION AND CONFINEMENT OF LOW ENERGY

SOLAR PARTICLES BY THE FLARE PLASflA DISTURBANCE

E. C. Roelof1, P. van Nes2, R. Relnhard3,

T. R. Sanderson-1 and K.-P. Wenzel3

*Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland 20707,

2Harshaw Chemie, 3454 PK DeMeern, The Netherlands

•'European Space Research and Technology Center, ESA, 2200 AG Noordwijk, The

Netherlands

Low energy ions (~ 100 keV) in solar flare events are strongly affected

by the subsequent propagation of the flare plasma disturbance through two

mechanisms: (1) acceleration near the ehock, and (2) partial confinement

behind the compressed magnetic fields behind the shock. These effects are

strongest at the lower energies, so they are graphically revealed in the

comparison of time histories of ion intensities from 35 keV to 1.6 MeV as

measured by the DFH experiment on ISF.E-3. The two effects are usually

difficult to separate, because particles accelerated and left downstream of

the shock will also propagate into (and behind) the comppression region.

However, the separation was possible in the event of June 6, 1979 (during STIP

Interval No. VI), the second largest event observed on ISEE-1 (van Nes et al.,

JGR, 90, in press). The DFH anisotropy measurements establish that the lowenergy ions passed nearly adiabatically through an almost perpendicular shock

and that they were confined behind a series of complex discontinuities in the

compressed magnetic field (~ 40 nT), the first of which followed the shock by

4 minutes. We suggest that this confinement by magnetic discontinuities may

also be an essential part of the structure of ESP events where the more usual

observational conditions do not allow the clear separation of acceleration

from confinement effects.

36
Variatio n i n Elementa l Compositio n o f Severa l MeV/Nucleo n

Particle s Observed i n Interplanetar y Space

R.E. McGuiret , T.T. von Rosenvinge , and D.V. Reame s

Code 661, NASA/Goddar d Space Fligh t Center,

Greenbelt , MO 20771 USA

'Als o Oept. of Physic s and Astronomy, Universit y of Maryland ,

Colleg e Park , MD 2074? USA

We hav e surveyed over six years of accumulate d ISEE-3 and IMP-8

dat a t o study variation s i n elementa l relativ e abundance s amon g

t he differen t population s of energeti c (1.5 to >10 MeV/nuc ) ion s

seen in interplanetar y space. We want to determin e what

systemati c difference s i n compositio n migh t exis t between flare -

accelerate d particle s an d th e locally-accelerate d particl e

population s associate d wit h some interplanetar y shocks. By more

clearl y distinguishin g loca l shock effects, we hope to better

establis h the criteri a governin g the selectio n of those sola r

events from whic h a baselin e of sola r energeti c part.icle

compositio n i s defined . W e examin e elementa l compositio n i n sola r

event s as a functio n of relativ e connectio n longitud e between the

flar e sit e an d th e observin g spacecraft , specificall y t o search

f o r an y signature s whic h migh t hel p t o distinguis h corona l

transpor t effects from the direc t acceleratio n of particle s over

an extende d range of solar longitude s by corona l or interplanetar y

shocks. We wil l als o address the questio n of source populatio n

signature s i n other kind s o f energeti c particl e events ; e.g.

corotatin g nucleo n streams.

To be presented by: R.E. McGuir e

Correspondenc e addres s Dr. Rober t E. McGu i re

Code 661

NASA/Goddar d Space Fligh t Cente r

Greenbelt , MR 20771 USA

'37
A Simulation Study of Two Major Events in the Heltoaphere During the Present

Sunspot Cycle

S.-I. AKASOFU, WEI Sun and C. FRY (Geophysical Institute, University of

Alaska, Fairbanks, AK 99701)

W. FILLIUS (University of California, San Diego, La Jolla, CA 92093)

WEI SUN (On leave from Institute of Geophysics, Academia Sinica, Beijing,

China)

M. DRYER (Space Environment Laboratory, NOAA, Boulder, CO 80303

The two major disturbances in the heliosphere during the present sunspot

cycle, the event of June - August, 1982 and the event of April - June, 1978,

are simulated by the method developed by Hakamada and Akasofu (1982).

Specifically, we attempt to simulate effects of six major flares from three

active regions in June - July, 1982 and April - Hay, 1978, respectively. A

comparison of the results with the solar wind observations at Pioneer 12 (f

0.8 au), ISEE-3 (~ 1 au), Pioneer 11 (~ 7-13 au) and Pioneer 10 (~ 16-28 au)

suggests that some major flares occurred behind the disk of the sun during the

two periods. Our method provides qualitatively some information as to how

such a series of intense solar flares can greatly disturb both the Inner and

outer heltosphares. A long lasting effect on cosmic rays is discussed in

conjunction with the disturbed heliosphere.

The three-dimensional geometry of the heliospheric current sheet seen

from fixed points In interplanetary space Is also constructed for itU-.ilized

(sinusoidal) magnetic neutral lines (equators), several observed magnetic

equator. The development of distortion of the solar current sheet caused by a

solar flare Is also simulated.

38
A Transient, Three-Dimensional MHD Model

For Numerical Simulation of Interplanetary Disturbances

by

S. M. Han1, S. T. Wu2 and M. Dryer3

1. Department of Mechanical Engineering, Tennessee

Technological University, Cookeville, TN. 38501

USA

2. Department of Mechanical Engineering, University

of Alabama in Huntsville, AL. 35899, USA

3. Space Environment Laboratory, NOAA, Boulder, CO.

80303, USA

ABSTRACT

Three-dimensional , time-dependen t MHD wave propagation s

throug h a stead y inhomogeneou s MH D flo w expandin g wit h

supersonic, superalfvenic speeds are examined by a MHD numerical

model based on the Lax-Wendroff finit e differenc e method.

The background steady supersonic, superalfveni c MHD flow is

obtaine d numericall y b y treatin g th e radia l coordinat e

parabolically . In this manner, a three-dimensiona l steady MHD

flo w can be obtained by a two-dimensiona l time-dependen t MHD

formulation. Transient MHD waves are generated by introducing a

perturbation at the lower radial boundary. Resulting development

and propagatio n of three-dimensiona l MHD wave s through the

background flow are simulated by the full three-dimensional timedependent MHD model.

Detailed discussion s on the formulatio n of the steady and

unsteady MHD models and descriptions of the numerica l schemes are

presented. Example computations are performed to demonstrate the

validity of formulation and capabilities of the numerica l models.

Numerica l results exhibit physically realistic propagation of MHD

waves and their interactions wit h the background flow.

Abstract submitted to STIP Symposium on Restrospective Analyses

a n d Futur e Coordinate d Intervals, Le s Diablerets, Switzerland ,

June 10-12, 1985
PRELIMINARY SUMMARY OF THE OBSERVATIONS MADE DURING

STIP INTERVAL NO. XV, 12-21 FEBRUARY 1984

S. R. Kane

Space Sciences Laboratory, University of California, Berkeley, California, USA

A number of energetic solar flares occurred during STIP Interval No. XV.

Perhaps the most interesting flare was the one on 16 February 1984 (-\-0900 UT) .

Although this flare was located ^40° behind the west limb of the sun, the X-ray

and radio emissions were detectable from the earth. Also a large increase in

the high energy particles was detected by the ground-based neutron monitors.

The high energy X-ray source was viewed stereoscopically by instruments aboard

two spacecraft, ICE and PVO. The PVO measurements show that the flare was very

intense and appeared weak from the earth because most of the emission source was

occulted by the photosphere. A coronal shock was also observed. Observational

characteristics of this and other flares during STIP Interval No. XV will be presented, and their implications regarding the acceleration and propagation of particles and the coronal shocks will be briefly discussed.

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Uf.'UCUAL KECURRKNCY OF EKUPTIVI-: PROMINENCES OF 20 APHIL 1<J8'l

BY

B. Rompolt

Astronomical Observatory of Wroclaw University

Poland

ABSTRACT

By means of the Large Coronograph of the Wroclaw Astronomical Observatory

a sequence of limb flares and eruptive prominences has been observed in Ha at

the east solar limb (SI9-E) on 20 April 1984, during the STIP Interval XVI.

Uncomrr.cnness of the event lies in the fact that three recurrent eruptive

prominences have been ejected from the same limb active region during the

interval of 3 hours and 45 minutes only. The first eruption start at 0717 UT,

the second at 0741 UT (24 minutes later!), and the third one at 1102 UT. This

is the shortest time ever observed between the consecutive ejections of the

recurrent eruptive prominences. This event gives the evidence that in an

active region the magnetic field forming the skeleton of the eruptives can be

rebuilt even in a tim e scale of half an hour. These three eruptive

prominences should induce specific phenomenan in the outer corona and

interplanetary space. The evolutionary characteristics of all observed events

occurred at the east limb on 20 April 1984 are also given and discussed in the

paper.

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THE VARIABLE NATURE OF THE SOLAR WIND INTERACTION

WITH COMET HALLEY AS IT APPROACHES THE SUN*

K.F. Rammer, D.A. Mendis and H.L.F. Houpis

EE&CS Department Mail Code C-014

University of California, San Diego

La Jolla, California 92093 USA

The different modes of interaction of the solar wind with Comet Halley,

as it approaches the sun, are discussed. At large heliocentric distances the

solar wind penetrates unimpeded on to the surface. This causes electrostatic

charging and blow-off of fine dust from the surface; a process that is

modulated by the solar wind flux. The observed irregular brightness

variations of the comet between 11 and 8 AU (inbound) is explained along these

lines. As the comet moves further in (closer than about 5 AU) mass loading of

the solar wind by the heavy cometary ions causes it to slow down, thereby

enhancing the convected IP magnetic field significantly. This magnetic

enhancement is the earliest and most sensitive signature associated with solar

wind mass loading. Stil l farther in (~ 3 AU), as tha mass loading approaches

a critical value, a weak (M =• 2) col lisionless standing shock forms, which

recedes upstream of the nucleus as the comet approaches the sun. The cometary

atmosphere becomes dense enough to stand off the solar wind ahead of the

nucleus and form a well-defined ionopause only when the comet is fairly close

to the sun (~ 2 AU). At this stage a wel1-developed magnetic barrier is

expected to separate the ionospheric and contaminated solar wind plasmas. An

"inner" shock may also then exist within the cometary ionopause, although this

too is expected to be weak (M - 2) due to the photo-chemical heating of the

cometary ionosphere.

Paper to be read at the STIP Symposium in Les Diablerets, Switzerland

(10-12 June, 1985)

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