Thermal electron transport in direct-drive laser fusion

Abstract

The experimental and theoretical aspects of electron thermal transport in direct-drive laser-fusion are reviewed. The Fokker–Planck equation and the flux-limited diffusion model, which is widely used in laser-fusion simulation codes, are described. After a discussion on the limitation of planar-target transport experiments, results of spherical experiments are surveyed. Solutions of the Fokker–Planck equations for cathode problems and for cases with stationary and moving ion density profiles are presented. Limitations of the flux-limited diffusion model are discussed in light of the Fokker–Planck results. Comparisons between experimental and theoretical results lead to the conclusion that the modeling of electron thermal transport in uniform spherical geometry does not require the existence of magnetic fields or anomalous plasma effects.