0000000000716743
AUTHOR
P. I. Porshnev
Nonlinear inverse bremsstrahlung and highly anisotropic electron distributions
A procedure is proposed to deal with the approximate solution of the kinetic equation for the velocity distribution function of electrons in a fully ionized plasma in the presence of strong, high frequency radiation. The Legendre polynomial expansion is applied after the kinetic equation has been written in an oscillating frame, where some directions are appropriately scaled, with the aim of making approximately isotropic, on the average, distributions that are otherwise anisotropic. The equations are derived for the isotropic part of the electron distribution in the scaled frame and for the scaling factor. The procedure is meant to display its potential in cases where the electron distribu…
Evolution of the electron distribution function in intense laser-plasma interactions
We report a numerical investigation of the time evolution of the electron distribution function (EDF) in a laser-embedded, fully ionized plasma. A distinctive feature of the calculations is removal of the frequently adopted assumption of small anisotropy of the EDF in velocity space. This requires solving a two-dimensional partial differential equation for the EDF. Within the adopted range of parameters, the EDF undergoes significant changes. An initially isotropic EDF transforms rapidly into an anisotropic one characterized by a longitudinal velocity scale larger than the perpendicular one. This longitudinal stretching persists for several cycles of the radiation field, implying the establ…