Improved treatment of electron thermal conduction in plasma hydrodynamics calculations

Abstract

The classical transport law for the hydrodynamic description of the electron heat flux breaks down in the nonequilibrium laser fusion plasma and an alternative expression for the electron heat flux vector must be used. The ad-hoc flux limit treatment used in present production level codes is analyzed and shown to provide physically plausible results but without providing any further insight into the properties of the plasma. Grad’s 13 moment method is proposed as an alternative to the conventional Fourier’s law expression for the heat flux. Numerical calculations confirm that this approach not only provides physically plausible results but provides them within a more fundamental framework than the ad-hoc flux limiting schemes and thus offers the possibility of gaining more insight into the flux limiting mechanism.