HEAO 1 observations of gamma-ray lines from a solar flare
Abstract
HEAO 1 observed gamma radiation, including the 2.223 MeV line of deuterium and the 4.43 MeV line of C-12, from a white-light solar flare of 1978 July 11. Line strengths over a 4 minute integration were 1.00 + or - 0.29 and 0.18 + or - 0.07 photons/sq cm s, respectively, and the continuum in the 1-5 MeV range fitted a spectrum 10 E to the -3rd photons/sq cm s keV. The 2.2 MeV line lagged 94 + or - 30 s behind the gamma-ray continuum, which itself was delayed about 20 s from the hard X-ray (not less than 40 keV) and microwave fluxes. This is the second flare for which both MeV-range lines and continuum have been observed, and the first for which simultaneous white-light observations exist. The prompt gamma-ray line (4.43 MeV) can be directly interpreted as an energy deposition of not greater than 7 x 10 to the 26th ergs per sec by energetic protons at photospheric depths. This is insufficient to maintain the white-light continuum by normal photospheric emission mechanisms.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1980
- DOI:
- 10.1086/183205
- Bibcode:
- 1980ApJ...236L..91H
- Keywords:
-
- Gamma Ray Spectra;
- Heao 1;
- Solar Flares;
- Solar Spectra;
- Carbon;
- Deuterium;
- Line Spectra;
- Photosphere;
- Spectral Line Width;
- Solar Physics