Inverse Bremsstrahlung Absorption Rate in an Intense Laser Field

摘要

Inverse bremsstrahlung is one of the important mechanisms for transferring energy from laser light to matter. The computer code LASNEX currently uses a simple physical model for this process for which there can be substantial corrections. The purpose of this investigation is to provide a model for the bremsstrahlung process that will be applicable over the whole range of interest for use in LASNEX. The derivation of the bremsstrahlung cross section and various approximate forms useful in the numerical calculations, and derivation of the expression for the energy absorption rate for a general distribution function and special forms for various approximations to the cross section are presented. The alternative methods of derivation of the energy absorption rate are discussed. Numerical results are presented along with comparison among the different expressions, and the validity of the assumptions and methods to relax the approximations are discussed. (ERA citation 04:039796)