The 6th Solar-B Science Meeting

Flare-associatedshock waves
observed in soft X-ray
NARUKAGE Noriyuki
Kwasan and Hida Observatories,
Kyoto University – DC3

Outline
1.

flare-associated shock wave

2.

propagation of shock wave
1.

Yohkoh/SXT (previous work)2.

Solar-B/XRT (observational plan)

3.

origin of shock wave (SOT)

4.

conclusion

5.

Appendix

1

flare-associatedshock wave

1

Flare-associated waves

Moreton wave

Ha
Hida/FMT etc.

discovered by Moreton (1960)
identified by Uchida (1968)

Chromospheric

EIT wave

EUV
SOHO/EIT
coronal

X-ray wave

soft X-ray
Yohkoh/SXT
coronalHe wave

He I
transition region

Thompson et al., 1999
Klassen et al., 2000
Biesecker et al., 2002
Khan and Hudson, 2000
Khan and Aurass, 2001
Narukage et al., 2002
Hudson, 2003
Narukage et al., 2004
Vrsnak et al., 2002

1

Moreton wave 1997/11/04
Eto et al., 2002

solar Flare Monitor Telescope (FMT)
Hida Obserbatory, Kyoto Univ.
The FMT observes four full disk images,
in Ha (line center and ＋/－ 0.8 Å) andcontinuum, and one solar limb image inHa center.

1
Observable region of flare waves
Moreton wave & X-ray wave

Flare waves usually
become visible
only at a distance ofmore than
100,000 km fromthe flare site.
Some flare waves
can propagate
up to distanceexceeding 500,000 km.

solar disk

Observable regionof flare waves
flare site

Propagation speed is
500 ~ 1500 km/s.

1

Uchida model (1968)
Uchida identified the Moreton
wave as the intersections of acoronal MHD fast shock front
and the chromosphere.

shock front

flare site

Moreton wave
solar disk

X-ray wave,
coronal counterpart ofMoreton wave

Moreton wave and filament eruption

1filament eruption

WGood correlation
between the direction ofwave propagation
andS
filament eruption.

jNW

E

In all Moreton
wave events,filament eruptions
were observed.

NW
W

N

E

Moreton waveSW

1

Magnetic fields
1997/11/04

Moreton waves tend
to propagate along
the global magneticfields.

1

Double shock generation
High-resoluble observation of Moreton wave with Hida/SMART

Solar Magnetic Activity Research Telescope(SMART)
Hida Obserbatory, Kyoto Univ.
The SMART is a state-of-the-art instrument thatcombines high resolution Ha full disk observationsand vector magnetic field measurements.

1

Double shock generation
Moreton waves, RHESSI & type II radio burst

Moreton wave
1.

~ 300 km/s

2.

~ 750 km/s

1

X-ray wave 1997/11/03
Narukage et al., 2002

Yohkoh / SXT[Soft X-ray]

Hida obs / FMT[Ha+0.8Å]

Quarter resolution

Running difference

Half resolution

1

Study of shock waveQuestion

How is the shock wave generated?
 key : filament eruption, magnetic field in flare region

How does the shock wave propagate?
 key : global magnetic field application : coronal seismologyHow much energy does spend on the shock generationand propagation?

 The shock observation in X-ray is indispensable,
because we need the physical quantities.

2

propagation ofshock wave
1. Yohkoh/SXT (previous work)2.1

Advantage of Yohkoh / SXT

Using Yohkoh / SXT images,
we can estimate the quantities of the X-ray wave.

Is the X-ray wave a MHD fast shock?

2.1

BEHIND

T2

Shock front

IX2

AHEAD

IX1
T1

B2

B1

θ2

θ1v2

v1

Using MHD Eq. (1)-(7), the observable
quantities (IX1,IX2,T1,B1,θ1) byYohkoh/SXT determine (v1,T2,B2,θ2,v2).

2.1

Is the X-ray wave a MHD fast shock?

Using this method,
we can estimate the quantities of the X-ray wave.
e.g.
The estimated fast shock speed (v1) is 400 ~ 760 km/s,
which is roughly agreement withthe observed propagation speed of the X-ray wave, 630 km/s.
The fast mode Mach number is 1.15 ~ 1.25.
These results suggest that the X-ray wave is an MHD fastshock propagating through the corona and hence is thecoronal counterpart of the Moreton wave.
Narukage et al. 2002, ApJ Letters 572, 109estimates
Machnumber
2.1

out of VOF?

X-ray wave observed on 2000/03/03,

The fast mode Mach number decreased.
 The timing when the Mach number become “1” consists
with the disappearance of the Moreton wave.
 We need more example!
Narukage et al. 2004, PASJ, 56, L5

2

propagation ofshock wave
2. Solar-B/XRTSolar-B
2.2

Using this method, we can examine
the possibility of wave detection with XRTand suggest the observational plan.

XRT–fieldofview
2.2
X-Ray Telescope

Observable regionof flare waves
flare site

Field of view
The observationsof X-ray waves require
the field of view aslarger than 512” x 512”.

512” x 512”1024” x 1024”

2.2


XRT – cadence & pixel size
X-Ray Telescope

Pixel size
The thickness of the wave isabout 40,000 km.
 The pixel size should besmaller than 4” x 4”.

BEHIND

AHEAD

Ix2

Ix1

Time cadence
The propagation speeds of X-ray wave are 500 ~ 1500 km/s.
 We can observe for less than 270 ~ 800 sec.
The observation needs as high cadence as possible.

The FOV, pixel size and time cadence are depend on thedata recorder capacity (15% of 8Gbits = 1.2Gbits = 150Mb).

XRT–
filter2.2
X-Ray TelescopeFilter selection
XRT has 9 filters.
We need 2 filters to estimate
the plasma temperature andemission measure.

XRT–
filterselection
2.2T (MK)2.25  2.78

em (cm-5)

10

27.0

8.5

27.3

 10
8.6

n (cm-3)10

 10[DN sec-1 arcsec-2]

Ix1

Ix2

Ix2 / Ix1

Entrance

280578

2.06

Thin Al Mesh

191444

2.33

Thin Al poly130347

2.68

CC poly
poly

71205

2.91

Ti
Ti poly
poly

36101

2.83

Thin
Thin BeBe1458

4.16

MediumMedium BeBe

164.61

MediumMedium AlAl

134.50Thick Al00--

Thick Be00--

(X=1.30)

I calculate the XRTintensities (Ix1 and Ix2)
and their ratios, using
my result of Yohkoh Xray wave.
To recognize the shock
against the background,the intensity ratio (=Ix2 /Ix1) should be larger
than 3.

XRT–filterselection
2.2
X-Ray TelescopeI examine the enough exposure time ( t ) to suppress
the effect of photon noise s.
s [DN] = N1/2 [p] * 300 (conversion factor) [e-/p] / 57 [e-/ DN](Ix2 – Ix1) t > 3s(t)Note : photon noise is superior to the other noise.
 Photon noise = N1/2 * 300e System noise < 30e Dark = 0.1e- / sec / pix I select the suitable filters for X-ray waves.

XRT–filterselection
2.2
pixel size

1” x 1”2” x 2”4” x 4”minimum
image size

512 x 512

256 x 256128 x 128

minimum exposure time [msec]

minimum FOV= 512” x 512”

Ix2 / Ix1

C poly378

95242.91

Ti poly

845

211

53

2.83

Thin Be

418

105

26

4.16

Medium Be

2411

603

151

4.61

Medium Al4541

1135

284

4.50

note : The influence of flare-loop brightness is not considered.

XRT–filter
selection
2.2
pixel size

1” x 1”2” x 2”4” x 4”

DN of Ix1 / Ix2 / AR at a exposure time of 250 msec
C poly18 / 51 / 1218

71 / 205 / 4872

282 / 821 / sat.

Ti poly

9 / 25 / 601

36 / 101 / 2404

143 / 405 / sat.

Thin Be

3 / 15 / 327

14 / 58 / 1308

56 / 233 / sat.

XRT–observational
plan
2.2
X-Ray TelescopeWe suppose the shock observation mode.

Following plan is a minimum-data-size plan.
selectionfiltersnote

C poly & Ti poly set
Wave & AR are not saturated.

exposure time

125 msec

pixel size2” x 2”

image size

384 pixel x 384 pixel768” x 768” FOV
144 k pixel
data size : 1728 kbits / image

compression

loss less

50%  864 kb / image

time cadence

15 secobs. time

900 sec

10 k pixel / sec
60 images (30 filter sets)= 50.6Mbits (4% of 1.2Gbits)

XRT–observational
plan
2.2
X-Ray TelescopeIn the X-ray waves observed with Yohkoh/SXT, it isdifficult to identify the shock waves only with the X-ray
observations.

The simultaneous observation with the ground
instruments is required.

The plasma velocity derived with Solar-B/EIS is also
important.
HaMoreton wave

Radio spectrum metric type II radio burst
Solar-B/EIS

plasma velocity

3

origin of shock wave

Solar-B/SOT

3

origin of Moreton wave

In all Moreton wave events, filament eruptions wereobserved.

In some cases of X-ray waves, X-ray ejecta were alsoobserved.

 What is the driver of waves?
2000/03/03

Moreton wave filament eruption
02:13:57

02:25:00

X-ray wave
X-ray ejecta
02:13:57

3


SOT target
Solar Optical Telescope

filament eruptions are strongly
related to the Moreton waves.
 We expect to detect the originof Moreton waves (shock waves).

We want to examine the shock
generation mechanism.
 We expect to observe themagnetic field structure in theshock generated regions.

Observable
region offlare waves

flare site164” x 328”conclusion

4XRT
 We can estimate the physical quantities of the shockwaves during the propagation. Especially, the change ofthe quantities is important.
SOT
 We can know the magnetic field structure in the shock-generated flare region.
 It may be possible to observe the shock generation.

 Using the above and ground-base observations,calculated global magnetic field, and numerical simulation,
we can progress the study of the flare-associated waves.

5Appendix
Solar-BThe flare-associated waves would occur associated with
10% of X or M-class flares.

If the flare frequency is the same as 11 years before, until
2009 there would be only a few waves per year. (This isunderestimate.)

Year

2006

2007

2008

2009

X-ray wave

1

1

2

11

Good observational plan is very important.

END
Thank you very muchfor your attention.

quantities of X-ray wave===================================================================
B_corona = B_photo * 0.5===================================================================
fr0=

1.9251738

fr =

v1x=
652.93857 v2x=Ix1=
15.601000 Ix2=
T1 =2.2499993 T2 =B1 =3.9905701
theta1= 60.000000

1.9251785 ( 2.4119677e-06)
501.06709
51.000599 (2.7754042

EM1=
em1=
n1 =

43.544198 EM2=
43.774151
27.042221 em2=
27.272174
8.4946216 n2 =8.6095980

Va =
Cs =
be =

492.46032
227.76080
0.25668277X =vsh=
Mf =1.3030961
652.93857
1.2033978

51.000722)

noise Photon noise = N1/2
 System noise < 30e Dark = 0.1e- / sec / pixConversion of photon to DN e3.64eV = e- + hole (in Si)
conversion factor :1photon = 300e- (except Thick Be)

 Photon
DN
57e- = 1DN e- XRT のみでの shock wave の判定は困難 Moreton wave (Ha), Type II burst (radio) など地上観測との連携が必要。EIS での速度場観測もshock 判定に使える。
 Moreton wave の発生には filament eruption が必ず伴う  shock wave の origin か？  SOTの高分解観測に期待。

DATA
 Capacity
 Total : 8Gbits XRT : 15% = 1.2Gbits
 Loss less compress  50%

 Data size [bits] = pix * pix *12bits