fl230.kiplinger01 Posted: 24-Feb-96 Updated: 10-Feb-96, 10-Nov-96 Events specified: Flare of 20-Oct-95 06:00 UT
Alan Kiplinger (U. Colorado and NOAA/SEL) Nariaki Nitta (LMSAL) Sergi Lesovoy (SSRT) Jun Sato (NAOJ/GUAS)
An outstanding example of a purely progressive hardening (i.e. no soft-hard-soft impulsive behavior) hard X-ray and interplanetary proton event occurred on 20 October, 1995. This event was imaged by Yohkoh in both soft and hard X-rays and was simultaneously imaged in microwaves (5.8 GHz) by a new Russian interferometer (the Siberian Solar Radio Telescope, SSRT) during its third day of 2-D observations. Preliminary inspection of both HXT and SSRT microwave imaging reveals a double source in both hard X-rays and microwaves that are separated by about 1 arc minute. We propose to conduct a comprehensive study of this well observed progressively hardening hard X-ray/proton event, collecting and analyzing all available data (HXT, SXT, SSRT, BATSE, Nobeyama, etc.)
Update 10-Nov-96
On 20 Oct. 1995 at 6:00 UT, a solar flare/interplanetary proton event occured in a western active region (A.R. 7912). The solar event was well observed by many observatories including Yohkoh. This is a very comprehensive study of an unusual and inportant class of event. Hard X-ray data from BATSE reveals signatures that would have allowed prediction of interplanetary protons a full 10 minutes before the soft X-ray fluxes peaked. Data from all possible sources is being analyzed and combined. This data includes particle data from WIND, an excellent series of power law spectral fits from BATSE, microwave spectra from the Nobeyama polarimeter, 2-D imaging and 1 D imaging from the Siberia Solar Radio Telescope H-alpha from the SOONSPOT system, and KPNO magnetograms (coronagraph data is being pursed in Asia). The YOHKOH software has been installed and is running on the P.I.'s Dec Alpha and SXT movies of the preflare (half resolution) and flare (full resolution) data have been studied in the various bands. Faint moving loops are seen over the main flare site 30 minutes prior to the HX emission which may be associated with a simultanous CME (a 440 km shock hit earth 2 days after the event that was produced near the time of the flare). Alignment of the SXT, HXT, microwave and H-alpha images is in progress. It appears that the main soft x-ray loop spans the neutral line to connect near the two H-alpha ribbons. A particle code, reconnection model is being modelled after this event (with Isidorus Doxus).