coronal hard x-rays prior to rhessi h. s. hudson space sciences lab, uc berkeley
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Coronal hard X-rays prior to RHESSI
H. S. Hudson
Space Sciences Lab, UC Berkeley
Coronal hard X-rays prior to RHESSI
H. S. Hudson
Space Sciences Lab, UC Berkeley
Yohkoh
Outline
• Review of metric radio morphology and physics
• The “extended flare” (Frost & Dennis, OSO-7, Kiplinger, Cliver et al.)
• Some Yohkoh coronal observations - cf Tomczak & Masuda presentations
• Comments about the physics
ISSI, October 2, 2006
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Sunspot cycle maximum Sunspot cycle minimum
The solar corona
ISSI, October 2, 2006
Schrijver-DeRosa PFSS example
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G. A. Gary, Solar Phys. 203, 71 (2001)
(vA ~ 200 -1/2 km/s)
CH
Distribution of coronal plasma
ISSI, October 2, 2006
Overview of metric solar burst phenomenology, courtesy Hiraiso Observatory
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Coronal radio emission at metric wavelengths
• Type I “noise storm” Not well understood?• Type II “slow drift burst” Large-scale shock wave• Type III “fast drift burst” Electron beam• Type IV “extended flare” Relativistic electrons• Type V Electron beam• U-burst Electron beam• …
ISSI, October 2, 2006
Coronal hard X-ray sources
• March 30, 1969 event (Frost & Dennis, 1971)
• Two OSO-7 events (Hudson 1978, Hudson et al. 1982)
• Review paper (Cliver et al. 1986) including front-side events
• Hard X-rays and protons (Kiplinger, 1995)
• Yohkoh observations (cf. Masuda, Tomczak)
• An omission from this talk: HXIS
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Frost & Dennis 1971
Enome & Tanaka 1971(3.5 GHz)
March 30, 1969:X-rays and Microwaves
No H flare, ~W105
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Palmer & Smerd, 1972
March 30, 1969: meter waves (Culgoora)
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OSO-7 event of Dec. 14, 1971
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X-rays
Electrons
OSO-7 event ofJuly 22, 1972
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May 13, 1981 - a unique Hinotori event, @ 6.6 x 104 km
Loughhead et al. 1983Tsuneta et al. 1984
Kawabata et al. 1983
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QuickTime™ and aTIFF (LZW) decompressor
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Over-the-limb events by 1986
Hudson, 1986
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Kane 1983: PVO & ISEE-3 stereo observations!
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Kane 1983: PVO & ISEE-3 stereo observations!
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Kane 1983: PVO & ISEE-3
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Cliver et al. 1986gradual HXR events
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Cliver et al. 1986
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Cliver cartoon
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Some disagreement regardingmicrowave-richness? Kiplinger, 1995
Cliver et al. 1986
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Hard X-ray association with SEPs
Kiplinger, ApJ 453, 973 (1995)
Squares => solar proton eventsFilled squares => progressive hardening
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Yohkoh contributions• A decade of observations with both soft and hard X-ray
imaging
• What are the (hard) X-ray counterparts of the metric phenomenology?
• What do hard X-ray images of extended flares look like?
• cf. Masuda and Tomczak presentations
ISSI, October 2, 2006
Metric burst-type scorecard• Type I - observed soft X-rays from magnetic cusp
(streamer) regions?
• Type II - observed soft X-rays from blast waves
• Type III - identified channels with soft X-ray jet trajectories
• Type IV - observed hard X-rays from moving source?
• Type V - ??
• U-burst - identified channels with soft X-ray jet trajectories
Not much hard X-ray progress?
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Soft X-rays from blast waves
QuickTime™ and aGIF decompressor
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Hudson et al. 2003
Khan & Aurass 2002
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Hard X-rays from ejecta
Hudson et al. 2001
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The 2001 April 18 event
• A large fast-moving hard X-ray source appeared above the limb, in association with a 17-GHz microwave source
• Association with m-wave phenomenology is problematic, but there was a type-II-like event
• Interpretation suggests a plasmoid (expanding loop) in which nonthermal pressure may dominate (??)
• Unique Yohkoh event in the middle corona?
ISSI, October 2, 2006
Conclusions
• Pre-RHESSI observations, both direct and limb-occulted, showed a wide variety of coronal hard X-ray emissions
• The coronal sources could be associated with various metric burst types, or not (eg., May 13, 1981)
• Some of the coronal sources showed exceptionally flat hard X-ray spectra; there is a pattern of gradual hardening
• The most interesting sources are probably the ones distinct from the loop-top soft X-ray sources, ie non-thermal in nature
ISSI, October 2, 2006
Particles in the PFSS context
• Elliott proposal
• Fields and particles compared
• Sources of particles
• Stability issues
• Convenience of Schrijver-DeRosa software
• Suitability of PFSS modeling
ISSI, October 2, 2006
Proposal for a review paper
• The March 30, 1969 event was somewhat analogous to the Carrington event - ausgezeichnet
• There was copious literature, at the time, but no synthesis
• Thanks to this workshop, we [will] know a lot more about the processes involved
• Would a review of this single event, based on secondary sources be worthwhile? Or should it just be a part of the main overview paper?
• Another possible single-event paper would be the May 13 1981 event, but I think it is less representative