Electron-beam evolution in partially ionized hydrogenic plasma with return currents

Abstract

view Abstract Citations (13) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electron-Beam Evolution in Partially Ionized Hydrogenic Plasma with Return Currents Syniavskii, D. V. ; Zharkova, V. V. Abstract This paper presents the kinetic equation solution for beam electrons injected during solar flares from the corona to the chromosphere, consisting of hydrogenic plasma with partial ionization. The electrons are considered to lose their energy both in collisional processes with the charged and neutral species of ambient plasma and in ohmic heating by return currents induced in the plasma by beam electrons. The evolution of the energy and angular distributions of energetic electrons is calculated as functions of the column density. The bulk of the electron-beam energy stored in low-energy electrons is shown to be lost in the ambient plasma heating, less via Coulomb collisions at the lower corona and more via ohmic dissipation at the upper chromosphere. More energetic electrons with energies above 120 keV can reach the chromospheric levels with a weak ionized plasma, where a decrease of the Coulomb collisions and the induced electric field of a return current produce beams as well directed as on the top boundary. The X-ray bremsstrahlung polarization is shown to be positive in the range 5%-10%. It is very sensitive to the emergent photon energies below 40 keV and to angles of view for all of the X-ray radiation range. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1994 DOI: 10.1086/191897 Bibcode: 1994ApJS...90..729S Keywords: Beam Injection; Electron Beams; Hydrogen Plasma; Kinetic Equations; Particle Acceleration; Solar Flares; Angular Distribution; Distribution Functions; Energy Dissipation; Fokker-Planck Equation; Plasma Heating; Solar Transition Region; Solar Physics; ACCELERATION OF PARTICLES; PLASMAS; SUN: FLARES; SUN: X-RAYS; GAMMA RAYS full text sources ADS |