Hard x-ray imaging observations of solar hot thermal flares with the Hinotori spacecraft
Journal Article
·
· Astrophys. J.; (United States)
Two solar hard X-ray bursts of a new type (hot thermal flare) were observed with hard X-ray imaging telescopes and other instruments on Japanese spacecraft Hinotori. The flares have no clear impulsive phase below 40 keV and emit intense hard X-rays (10--50 keV) with extremely steep spectra from a small region with size (FWHM) of 10''--20''. This source contains a hot thermal plasma of (3--3.5) x 10/sup 7/ K with an emission measure of the order of 10/sup 49/ cm/sup -3/. One of the flares occurred just on the limb, and the centroid of the hard X-ray (14-38 keV) source was located at (6 +- 3) x 10/sup 3/ km above the photosphere. It is concluded that the energy continuously released goes into heating rather than acceleration almost throughout the flare. Typical impulsive flares may usually have a similar nature in the later phase (gradual phase) of the flare evolution. The number density of the hard X-ray emitting region was higher than (6-10) x 10/sup 10/ cm/sup -3/ even in the initial phase of the flare, probably due to its low altitude. We infer that this high density made acceleration difficult, and therefore unusually intense heating occurred from the start of the flare.
- Research Organization:
- Institute of Space and Astronautical Science
- OSTI ID:
- 5923418
- Journal Information:
- Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 284:2; ISSN ASJOA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hard X-ray imaging of the solar flare on 1981 May 13 with the Hinotori spacecraft
Hard X-ray imaging of a solar limb flare with the x-ray telescope aboard the Hinotori satellite
Heating and acceleration processes in hot thermal and impulsive solar flares
Journal Article
·
Tue May 15 00:00:00 EDT 1984
· Astrophys. J.; (United States)
·
OSTI ID:6126919
Hard X-ray imaging of a solar limb flare with the x-ray telescope aboard the Hinotori satellite
Journal Article
·
Fri Jul 15 00:00:00 EDT 1983
· Astrophys. J., Lett. Ed.; (United States)
·
OSTI ID:5542582
Heating and acceleration processes in hot thermal and impulsive solar flares
Journal Article
·
Thu Feb 28 23:00:00 EST 1985
· Astrophys. J.; (United States)
·
OSTI ID:5740170