Studies on the 2002 July 23 Flare with RHESSI

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Studies on the 2002 July 23 Flare with RHESSI

• Ayumi ASAI
• Solar Seminar, 2003 June 2

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RHESSI (???)Reuven Ramaty High Energy Solar
Spectrospic Imager
Launched on 2002 Feburary 5 weight
290kg length 2.2m (solar panel 5.7m) cost
70M
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RHESSI

• energy range 3 keV 17 MeV
• imaging
• maximum spatial resolution
• beam size 3.3 FWHM
• spectroscopy
• high spectral resolution 110 keV

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2002 July 23 Flare

• 2002-July-23 0015UT
• GOES X4.8
• NOAA 0039
• (near south-east limb)

GOES flux
Ha image taken with Sartorius Telescope
NoRH 17GHz
NoRH 34GHz
0000
0100
0200
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EUV(195Å)?
EUV (195Å) images obtained with TRACE
East
West
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Paper List

• The Determination and Use of Mean Electron Flux
  Spectra in Solar Flares J.C. Brown
• The Injected Power in Solar Flare
  Bremsstrahlung-Producing Electrons - Death to the
  'Low Energy Cutoff A.G. Emslie
• RHESSI Imaging Spectroscopy of the Large
  Gamma-Ray Flare of July 23, 2002 A.G.
  Emslie
• H-alpha line polarization in the major flare of
  2002 July 23 I. Observations and data analysis
  N. Firstova
• Why there was no Solar Energetic Particle Event
  Associated with the RHESSI Flare of 2002 July 23?
  N. Gopalswamy
• Electron Bremsstrahlung Hard X-ray Spectra,
  Electron Distributions and Energetics in the 2002
  July 23 Solar Flare G.D. Holman
• First gamma-ray images of a solar flare G.J.
  Hurford
• Explanations for Deviations from Power-Law
  Behavior in the Hard X-ray Spectrum of the July
  23, 2002 Solar Flare E.P. Kontar

• Hard X-ray sources and motions in the July 23,
  2002 gamma-ray flare S. Krucker
• Bob Lin's opus
• Implications of RHESSI Neutron-Capture Line
  Measurements on the Photospheric 3He/H ratio and
  Particle Scattering in the Coronal Magnetic Loop
  R.J. Murphy
• Regularized Dynamic Electron Flux Spectra in the
  July 23, 2002 Solar FlareM. Piana
• High-resolution observation of the solar
  positron-electron annihilation lineG.H. Share
• Directionality of flare-associated
  alpha-particles at the Sun G.H. Share
• High-Resolution Spectroscopy of Gamma-Ray Lines
  from the X-Class Solar Flare of 23 July, 2002
  D.M. Smith
• RHESSI observation of the 1809 keV line from
  Galactic 26Al D.M. Smith
• Radio and hard X-ray images of high-energy
  electrons in a compact X-class solar flare S.M.
  White

17 papers!
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Paper List

• The Determination and Use of Mean Electron Flux
  Spectra in Solar Flares J.C. Brown
• The Injected Power in Solar Flare
  Bremsstrahlung-Producing Electrons - Death to the
  'Low Energy Cutoff A.G. Emslie
• RHESSI Imaging Spectroscopy of the Large
  Gamma-Ray Flare of July 23, 2002 A.G.
  Emslie
• H-alpha line polarization in the major flare of
  2002 July 23 I. Observations and data analysis
  N. Firstova
• Why there was no Solar Energetic Particle Event
  Associated with the RHESSI Flare of 2002 July 23?
  N. Gopalswamy
• Electron Bremsstrahlung Hard X-ray Spectra,
  Electron Distributions and Energetics in the 2002
  July 23 Solar Flare G.D. Holman
• First gamma-ray images of a solar flare G.J.
  Hurford
• Explanations for Deviations from Power-Law
  Behavior in the Hard X-ray Spectrum of the July
  23, 2002 Solar Flare E.P. Kontar

• Hard X-ray sources and motions in the July 23,
  2002 gamma-ray flare S. Krucker
• Bob Lin's opus
• Implications of RHESSI Neutron-Capture Line
  Measurements on the Photospheric 3He/H ratio and
  Particle Scattering in the Coronal Magnetic Loop
  R.J. Murphy
• Regularized Dynamic Electron Flux Spectra in the
  July 23, 2002 Solar FlareM. Piana
• High-resolution observation of the solar
  positron-electron annihilation lineG.H. Share
• Directionality of flare-associated
  alpha-particles at the Sun G.H. Share
• High-Resolution Spectroscopy of Gamma-Ray Lines
  from the X-Class Solar Flare of 23 July, 2002
  D.M. Smith
• RHESSI observation of the 1809 keV line from
  Galactic 26Al D.M. Smith
• Radio and hard X-ray images of high-energy
  electrons in a compact X-class solar flare S.M.
  White

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Imaging
Krucker et al. (2003) ApJL

• 4 HXR sources
• 3 footpoint sources (gt 30keV)
• 1 coronal sources (lt30 keV)
• comparison between their positions with those of
  EUV(TRACE)/Ha sources
• footpoint sources ? flare ribbons
• coronal sources ? above post-flare loops

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HXR Sources
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Evolution of HXR Sources
f3
f1
velocity
count
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Radio Sources
White et al. (2003) ApJ

• Radio data Nobeyama NoRH

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TRACE
12-20keV

• 17 GHz sources are co-spatial with coronal HXR
  sources

17GHz
12-20keV
100-150keV
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g-Ray Imaging
Hurford et al. (2003) ApJ

• This flare is the first, and the only one so far,
  g-ray line event
• direct indication of the spatial properties of
  accelerated ions near the sun
• 2.223 MeV line
• narrow deuterium line (neutron capture)
• dense plasma (chromosphere)
• red-shifted ? precipitation

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g-Ray Lines

• ion acceleration
• collisions with the solar atmosphere
• ?excited nuclei
• ?emit prompt nuclear de-excitation lines
• secondary process
• ?neutron capture line (2.223 MeV)
• ?positron-annihilation line (511 keV)

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Imaging of g-Ray Source
sun
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No Brightening in Ha
1s circle error 6
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Discussions

• 2.2 MeV source was found to be displaced from the
  main bright point
• ?there are significant differences in location
  and/or morphology between the electron- and
  ion-associated sources
• ion- and electron-light curves are similar to
  each other
• ?common acceleration process

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Spectroscopy
Holman et al. (2003) ApJ

• integrated photon flux spectra 10-300 keV
• fitting
• isothermal double power low (nonthermal)
• electron flux distribution
• thin-target / thick-target
• energy content

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Fitting
100keV
10keV
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Evolution of T / EM
temperature
GOES
emission measure
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Thick-Target
electron indices
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Energetics
GOES
RHESSI
nonthermal
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Discussions

• fitting of nonthermal electron
• double poewr law distribution with low energy
  cut-off 20-40 keV
• minimum total energy deposited by nonthermal
  electrons 2.61031 erg
• ?comparable to thermal energy input
• ?require imaging spectroscopy

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Imagin Spectroscopy
Emslie et al. (2003) ApJ

• Evolution of spectra at 4 HXR sources
• Temperature, Emission measure

N
M
C
S
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• fitting
• C thermal
• N, S, M nonthermal

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T

• coronal source (C)
• temperature K
• EM J
• softer spectral index than footpoint sources
  (N,S,M)

EM
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Summary

• Flare studies with RHESSI
• Imaging, Spectroscopy
• other big flares ?
• 2003 Mar 17/18
• 2003 May 27/28/29
• 18th paper on July 23, 2002 flare (by Asai
  et al.) ?

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Double Power Low
indices
single power law
break energy