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Directivity of 100 keV-1 MeV photon sources in solar flaresStereoscopic observations of 0.1-1.0 MeV photon sources in solar flares made with spectrometers aboard the ISEE 3 and PVO (Pioneer Venus Orbiter) have been analyzed to determine the directivity of the photon sources and its possible dependence on photon energy. During the period October 1, 1978-October 31, 1980, a total of 44 solar flares were observed simultaneously by the two instruments. Of these, 39 flares were in full view of both the instruments, the remaining five being partially occulted by the photosphere from the line of sight of at least one instrument. The view angles theta(P) and theta(I) of the PVO and ISEE 3 instruments with respect to the outward solar radius at the flare site varied from one flare to another and were in the range 9-88 deg. The difference between the two view angles varied from 1 deg to 66 deg. The observations of differential photon energy spectra averaged over more than about 16 s do not indicate any systematic directivity. In most flares the directivity of 0.1-1.0 MeV photon sources is found to be less than about 2.5.
Document ID
19880044721
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kane, S. R.
(California, University Berkeley, United States)
Fenimore, E. E.
(California Univ. Berkeley, CA, United States)
Klebesadel, R. W.
(California Univ. Berkeley, CA, United States)
Laros, J. G.
(Los Alamos National Laboratory NM, United States)
Date Acquired
August 13, 2013
Publication Date
March 15, 1988
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 326
ISSN: 0004-637X
Subject Category
Solar Physics
Report/Patent Number
AFGL-TR-88-0226
AD-A199509
Accession Number
88A31948
Funding Number(s)
CONTRACT_GRANT: NAG2-393
CONTRACT_GRANT: NGL-05-003-017
CONTRACT_GRANT: NASA ORDER A-47981-P
CONTRACT_GRANT: NAG5-376
Distribution Limits
Public
Copyright
Other

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