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 Sunspot cycle maximumSunspot cycle minimum The solar corona

ISSI, October 2, 2006 Schrijver-DeRosa PFSS example

ISSI, October 2, 2006 G. A. Gary, Solar Phys. 203, 71 (2001) (v A ~ 200  -1/2 km/s) CH Distribution of coronal plasma 

ISSI, October 2, 2006 Overview of metric solar burst phenomenology, courtesy Hiraiso Observatory

ISSI, October 2, 2006 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-burstElectron 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

ISSI, October 2, 2006 Frost & Dennis 1971 Enome & Tanaka 1971 (3.5 GHz) March 30, 1969: X-rays and Microwaves No H  flare, ~W105

ISSI, October 2, 2006 Palmer & Smerd, 1972 March 30, 1969: meter waves (Culgoora)

ISSI, October 2, 2006 OSO-7 event of Dec. 14, 1971

ISSI, October 2, 2006 X-rays Electrons OSO-7 event of July 22, 1972

ISSI, October 2, 2006 May 13, a unique Hinotori 6.6 x 10 4 km Loughhead et al Tsuneta et al Kawabata et al. 1983

ISSI, October 2, 2006 Over-the-limb events by 1986 Hudson, 1986

ISSI, October 2, 2006 Kane 1983: PVO & ISEE-3 stereo observations!

ISSI, October 2, 2006 Kane 1983: PVO & ISEE-3 stereo observations!

ISSI, October 2, 2006 Kane 1983: PVO & ISEE-3

ISSI, October 2, 2006 Cliver et al gradual HXR events

ISSI, October 2, 2006 Cliver et al. 1986

ISSI, October 2, 2006 Cliver cartoon

ISSI, October 2, 2006 Some disagreement regarding microwave-richness? Kiplinger, 1995 Cliver et al. 1986

ISSI, October 2, 2006 Hard X-ray association with SEPs Kiplinger, ApJ 453, 973 (1995) Squares => solar proton events Filled squares => progressive hardening

ISSI, October 2, 2006 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?

ISSI, October 2, 2006 Soft X-rays from blast waves Hudson et al Khan & Aurass 2002

ISSI, October 2, 2006 Hard X-rays from ejecta Hudson et al. 2001

ISSI, October 2, 2006 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 event, but I think it is less representative