Center-to-limb variations of characteristics of solar flare hard X-ray and gamma-ray emission

Abstract

view Abstract Citations (37) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Center-to-Limb Variations of Characteristics of Solar Flare Hard X-Ray and Gamma-Ray Emission McTiernan, James M. ; Petrosian, Vahe Abstract An analysis is presented of the observed distribution of fluxes and spectral indices of flares at X-ray and gamma-ray range, with particular emphasis on the variation with heliocentric longitude of these distributions and their moments. It is shown how these distributions can be used to set constraints on the distribution and average values of model parameters describing the characteristics of the accelerated electrons and flare plasma. A comparison of X-ray and gamma-ray spectral indices show that the spectrum of the accelerated electrons must flatten at higher energies. The Gaussian width of the pitch angle distribution of electrons beamed along the field lines and the convergence rate of the magnetic field are delimited. It is concluded that isotropic pitch angle distributions or distributions peaking perpendicular to the field lines, and field convergence rate with more than a fivefold increase in the magnetic field from corona to the photosphere can be ruled out. Publication: The Astrophysical Journal Pub Date: September 1991 DOI: 10.1086/170513 Bibcode: 1991ApJ...379..381M Keywords: Gamma Ray Bursts; Solar Electrons; Solar Flares; Solar Limb; Solar X-Rays; Electron Acceleration; Electron Distribution; Flux Density; Power Spectra; Solar Physics; GAMMA RAYS: BURSTS; PARTICLE ACCELERATION; RADIATION MECHANISMS; SUN: FLARES; SUN: X-RAYS full text sources ADS |