Internal tests and improvements of the Krook model for nonlocal electron energy transport in laser produced plasmas

Abstract

Electron thermal transport in a laser produced plasma cannot be described with a local approximation in many regions of a laser produced plasma because the electron mean free path is longer than the temperature gradient scale length. Since a Krook model for the electron Vlasov equation is analytically solvable in the nonlocal limit, one can find simple expressions for the electron thermal flux in the nonlocal limit, and these can be economically incorporated into fluid simulations. The Krook model provides reasonable descriptions of both preheat and flux limitation. We have analyzed the Krook model in a series of publications. Here we streamline the presentation of the model, show qualitatively just what the model predicts in certain situations, give internal tests to check the validity of the model, and provide more accurate analytic approximations to the integral formulas which the model gives rise to.