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Coronal hard X-rays prior to RHESSI

Coronal hard X-rays prior to RHESSI. H. S. Hudson Space Sciences Lab, UC Berkeley. Coronal hard X-rays prior to RHESSI. Yohkoh. H. S. Hudson Space Sciences Lab, UC Berkeley. Outline. • Review of metric radio morphology and physics

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Coronal hard X-rays prior to RHESSI

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  1. Coronal hard X-rays prior to RHESSI H. S. Hudson Space Sciences Lab, UC Berkeley

  2. Coronal hard X-rays prior to RHESSI Yohkoh H. S. Hudson Space Sciences Lab, UC Berkeley

  3. 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

  4. The solar corona Sunspot cycle maximum Sunspot cycle minimum

  5. Schrijver-DeRosa PFSS example

  6. Distribution of coronal plasma b CH G. A. Gary, Solar Phys. 203, 71 (2001) (vA ~ 200 b-1/2 km/s)

  7. Overview of metric solar burst phenomenology, courtesy Hiraiso Observatory

  8. 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 • …

  9. 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

  10. Frost & Dennis 1971 March 30, 1969: X-rays and Microwaves No Ha flare, ~W105 Enome & Tanaka 1971 (3.5 GHz)

  11. March 30, 1969: meter waves (Culgoora) Palmer & Smerd, 1972

  12. OSO-7 event of Dec. 14, 1971

  13. OSO-7 event of July 22, 1972 X-rays Electrons

  14. May 13, 1981 - a unique Hinotori event, @ 6.6 x 104 km Loughhead et al. 1983 Tsuneta et al. 1984 Kawabata et al. 1983

  15. Over-the-limb events by 1986 Hudson, 1986

  16. Kane 1983: PVO & ISEE-3 stereo observations!

  17. Kane 1983: PVO & ISEE-3 stereo observations!

  18. Kane 1983: PVO & ISEE-3

  19. Cliver et al. 1986 gradual HXR events

  20. Cliver et al. 1986

  21. Cliver cartoon

  22. Cliver et al. 1986 Some disagreement regarding microwave-richness? Kiplinger, 1995

  23. Hard X-ray association with SEPs Squares => solar proton events Filled squares => progressive hardening Kiplinger, ApJ 453, 973 (1995)

  24. 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

  25. 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?

  26. Soft X-rays from blast waves Hudson et al. 2003 Khan & Aurass 2002

  27. Hard X-rays from ejecta Hudson et al. 2001

  28. 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?

  29. 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

  30. 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

  31. 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

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