Directivity of high-energy emission from solar flares - Solar Maximum Mission observations

Journal Article · Sun Nov 01 04:00:00 EST 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165796· OSTI ID:5404186

Vestrand, W T; Forrest, D J; Chupp, E L; Rieger, E; Share, G H

The data base consisting of flares detected by the gamma-ray spectrometer (GRS) on board the Solar Maximum Mission (SMM) satellite is used to study the directivity of high-energy radiation. A number of observations are presented that, strongly indicate that the high-energy emission from flares is anisotropic. They are the following: (1) the fraction of events detected at energies above 300 keV near the limb is higher than is expected for isotropically emitting flares; (2) there is a statistically significant center-to-limb variation in the 300 keV to 1 MeV spectra of flares detected by the SMM GRS; (3) the 25-200 keV hard X-ray spectra measured during the impulsive phase by the SMM GRS show a center-to-limb variation; and (4) nearly all of the events detected at above 10 MeV are located near the limb. 38 references.

• Research Organization: New Hampshire Univ., Durham; Max-Planck-Institut fuer Extraterrestrische Physik, Garching, Germany, F.R.; Navy, E. O. Hulburt Center for Space Research, Washington, DC
• OSTI ID: 5404186
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 322; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
DATA BASE MANAGEMENT
DISTRIBUTION
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HARD X RADIATION
IONIZING RADIATIONS
MANAGEMENT
RADIATIONS
SOLAR ACTIVITY
SOLAR FLARES
VARIATIONS
X RADIATION