Flare-associated shock waves observed in soft X-ray

1
Flare-associated shock waves observed in soft
X-ray
The 6th Solar-B Science Meeting 09-Nov-2005
Kyoto, JAPAN

• NARUKAGE Noriyuki
• Kwasan and Hida Observatories,Kyoto University
  DC3

2
Outline

1. flare-associated wave
2. propagation of shock wave
3. Yohkoh/SXT (previous work)
4. Solar-B/XRT (observational plan)
5. counterpart of EIT waves
6. summary

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flare-associated wave
1
4
Flare-associated waves
1
Moreton wave HaHida/FMT etc.Chromospheric discovered by Moreton (1960)identified as the MHD fast-mode shock wave by Uchida (1968)
EIT wave EUVSOHO/EITcoronal Thompson et al., 1999Klassen et al., 2000Biesecker et al., 2002
X-ray wave soft X-rayYohkoh/SXTcoronal Khan and Hudson, 2000Khan and Aurass, 2001Narukage et al., 2002Hudson, 2003Narukage et al., 2004
He wave He Itransition region Vrsnak et al., 2002
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Moreton wave 1997/11/04
1
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) and continuum, and one solar limb image in Ha
center.
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Observable region of flare waves
1
Moreton wave X-ray wave

• Moreton waves usually become visibleonly at a
  distance of more than100,000 km fromthe flare
  site.
• Some flare wavescan propagateup to distance
  exceeding 500,000 km.

solar disk
Observable region of flare waves
flare site
Propagation speed is 500 1500 km/s.
(Smith and Harvey, 1971)
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Uchida model (1968)
1
Uchida identified the Moreton wave as the
intersections of a coronal MHD fast shock front
and the chromosphere.
shock front Moreton wave X-ray wave,coronal
counterpart of Moreton wave
solar disk
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Moreton wave and filament eruption
1
W
j
N
S
filament eruption
W
E
In all Moreton wave events, filament eruptions
were observed.
N
W
W
N
E
S
W
Moreton wave
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Global magnetic field
1
1997/11/04

• Moreton waves tend to propagate along the global
  magnetic fields.

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Double shock generation
1
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 that combines
high resolution Ha full disk observations and
vector magnetic field measurements.
Our latest work of the Moreton wave
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Double shock generation
1
Moreton waves, RHESSI type II radio burst

• Moreton wave
• 950 km/s
• 700 km/s
• Narukage et al., 2005

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X-ray wave 1997/11/03
1
Narukage et al., 2002
Hida obs / FMT Ha0.8Å Running difference
Yohkoh / SXTSoft X-ray Quarter resolution
Half resolution
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Study of shock wave
1

• Question
• 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 global coronal seismology
• How much energy does spend on the shock
  generation and propagation?
• ? The shock observation in X-ray is
  indispensable, because we need the physical
  quantities.

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propagation of shock wave
2

• 1. Yohkoh/SXT (previous work)

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Advantage of Yohkoh / SXT
2.1
Using Yohkoh / SXT images, we can estimate the
quantities of the X-ray wave.
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Is the X-ray wave a MHD fast shock?
2.1
BEHIND
AHEAD
Shock front
IX1 T1 B1 ?1 v1
IX2 T2 B2 ?2 v2
Using MHD Eq. (1)-(7), the observable quantities
(IX1,IX2,T1,B1,?1) by Yohkoh/SXT determine
(v1,T2,B2,?2,v2).
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Is the X-ray wave a MHD fast shock?
2.1
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 fast shock propagating through the corona and
  hence is the coronal counterpart of the Moreton
  wave.
• Narukage et al. 2002, ApJ Letters 572, 109

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estimated Mach number
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

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propagation of shock wave
2

• 2. Solar-B/XRT

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Solar-B
2.2
Using our method, we can examine the
possibility of wave detection with XRT
and suggest the observational plan.
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XRT field of view
2.2
X-Ray Telescope
Observable region of flare waves
flare site

• Field of viewThe observationsof X-ray waves
  require the field of view as larger than 512 x
  512.

512 x 512
1024 x 1024
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XRT cadence pixel size
2.2
X-Ray Telescope

• Pixel sizeThe thickness of the wave isabout
  40,000 km.
• Time cadenceThe propagation speeds of X-ray wave
  are 500 1500 km/s.

• ? The pixel size should besmaller than 4 x 4.
• We can observe for less than 270 800 sec.The
  observation needs as high cadence as possible.

BEHINDIx2
AHEADIx1
The FOV, pixel size and time cadence are depend
on the data recorder capacity (15 of 8Gbits
1.2Gbits 150Mb).
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XRT filter
2.2
X-Ray Telescope

• Filter selectionXRT has 9 filters. We need 2
  filters to estimatethe plasma temperature
  andemission measure.

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XRT filter selection
2.2
T (MK) 2.25 ? 2.78 2.25 ? 2.78 2.25 ? 2.78
em (cm-5) 1027.0 ? 1027.3 1027.0 ? 1027.3 1027.0 ? 1027.3
n (cm-3) 108.5 ? 108.6 (X1.30) 108.5 ? 108.6 (X1.30) 108.5 ? 108.6 (X1.30)
DN sec-1 arcsec-2 Ix1 Ix2 Ix2 / Ix1
Entrance 280 578 2.06
Thin Al Mesh 191 444 2.33
Thin Al poly 130 347 2.68
C poly 71 205 2.91
Ti poly 36 101 2.83
Thin Be 14 58 4.16
Medium Be 1 6 4.61
Medium Al 1 3 4.50
Thick Al 0 0 --
Thick Be 0 0 --
T (MK) 2.25 ? 2.78 2.25 ? 2.78 2.25 ? 2.78
em (cm-5) 1027.0 ? 1027.3 1027.0 ? 1027.3 1027.0 ? 1027.3
n (cm-3) 108.5 ? 108.6 (X1.30) 108.5 ? 108.6 (X1.30) 108.5 ? 108.6 (X1.30)
DN sec-1 arcsec-2 Ix1 Ix2 Ix2 / Ix1
Entrance 280 578 2.06
Thin Al Mesh 191 444 2.33
Thin Al poly 130 347 2.68
C poly 71 205 2.91
Ti poly 36 101 2.83
Thin Be 14 58 4.16
Medium Be 1 6 4.61
Medium Al 1 3 4.50
Thick Al 0 0 --
Thick Be 0 0 --
I calculate the XRT intensities (Ix1 and Ix2)and
their ratios, using my result of Yohkoh X-ray
wave.
To recognize the shock against the background,
the intensity ratio (Ix2 / Ix1) should be large.
Bold font A filter wheelNormal font B filter
wheel
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XRT filter selection
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 gt 3s(t)
• Note photon noise is superior to the other
  noise.
• Photon noise N1/2 300e-
• System noise lt 30e-
• Dark 0.1e- / sec / pix

? I select the suitable filters for X-ray waves.
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XRT observational plan
2.2
X-Ray Telescope

• We suppose the shock observation mode.
• Following plan is a minimum-data-size plan.

selection note
filter C poly Thin Al poly set Wave AR are not saturated.
exposure time 250 msec 125 msec Wave AR are not saturated.
pixel size 2 x 2 768 x 768 FOV144 k pixeldata size 1728 kbits / image
image size 384 pixel x 384 pixel 768 x 768 FOV144 k pixeldata size 1728 kbits / image
compression loss less 50 ? 864 kb / image
time cadence 15 sec 10 k pixel / sec60 images 50.6Mbits (4 of 1.2Gbits)
obs. time 900 sec 10 k pixel / sec60 images 50.6Mbits (4 of 1.2Gbits)
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counterpart ofEIT waves
3

• Solar-B/XRT

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EIT wave
3
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EIT wave
3

• Diffuse coronal wave appearing as an EUV
  emission front (Thompson et al. 1999)
• Primarily observed in EIT 195Å (1.6 MK)
• Speeds few hundred km/s
• propagates nearly isotropically and often
  globally
• Correlated with CMEs (Biesecker et al 2002)
• Models What is EIT wave? Big puzzle!
• fast magnetoacoustic waves(Wang 2000 Warmuth et
  al. 2001 Ofman Thompson 2002)
• super-Alfvenic shock waves(Cameron Uchida
  2001 Khan Aurass 2002)
• field line openings (Delanee 2000 Chen et al.
  2005)

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EIT wave
3

• Multi-wave lengthobservation ofEIT waves
• 195 A 1.5 MK
• 171 A 1.0 MK
• 284 A 0.7 MK
• 304 A 0.5 MK
• SXI open,Med Poly, Thin Be

Thin Al mesh
Thin Al mesh - Thin Al poly
Thin Al poly
XRT can observethe counterpart of EIT waves.
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summary
4

• Shock wave (X-ray wave)
• Using Solar-B/XRT, we can estimate the physical
  quantities of the shock waves during the
  propagation. Especially, the change of the
  quantities is important.
• Counterpart of EIT wave
• XRT can observe the counterpart of the EIT waves.
• ? I suppose the observation with C poly (shock
  wave), thin Al poly (shock and EIT wave) and thin
  Al mesh (EIT wave) filter sets.
• ? Using the XRT, ground-base observations,
  calculated global magnetic field and numerical
  simulation, we can progress the study of the
  flare-associated waves.

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END

• Thank you very much for your
  attention.