Astronomy and Astrophysics – Astronomy
Scientific paper
Oct 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...434..747p&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 434, no. 2, p. 747-755
Astronomy and Astrophysics
Astronomy
21
Bremsstrahlung, Coulomb Collisions, Electron Acceleration, Gamma Ray Astronomy, Gamma Ray Spectra, Pions, Radiative Transfer, Solar Flares, Solar Protons, Stellar Models, Synchrotron Radiation, Transport Properties, Chromosphere, Gamma Ray Observatory, Photosphere, Solar Corona, Solar Maximum Mission
Scientific paper
Recent observations have extended the spectra of the impulsive phase of flares to the GeV range. Such high-energy photons can be produced either by electron bremsstrahlung or by decay of pions produced by accelerated protons. In this paper we investigate the effects of processes which become important at high energies. We examine the effects of synchrotron losses during the transport of electrons as they travel from the acceleration region in the corona to the gamma-ray emission sites deep in the chromosphere and photosphere, and the effects of scattering and absorption of gamma rays on their way from the photosphere to space instruments. These results are compared with the spectra from so-called electron-dominated flares, observed by GRS on the Solar Maximum Mission, which show negligible or no detectable contribution from accelerated protons. The spectra of these flares show a distinct steepening at energies below 100 keV and a rapid falloff at energies above 50 MeV. Following our earlier results based on lower energy gamma-ray flare emission we have modeled these spectra. We show that neither the radiative transfer effects, which are expected to become important at higher energies, nor the transport effects (Coulomb collisions, synchrotron losses, or magnetic field convergence) can explain such sharp spectral deviations from a simple power law. These spectral deviations from a power law are therefore attributed to the acceleration process. In a stochastic acceleration model the low-energy steepening can be attributed to Coulomb collision and the rapid high-energy steepening can result from synchrotron losses during the acceleration process.
Marschhäuser Holger
McTiernan James M.
Petrosian Vahe
No associations
LandOfFree
Gamma-ray emission and electron acceleration in solar flares does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Gamma-ray emission and electron acceleration in solar flares, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gamma-ray emission and electron acceleration in solar flares will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1070529