Non-Spitzer heat flow in a steadily ablating laser-produced plasma

Abstract

Electron energy transport in a laser‐produced ablating plasma is modeled by the Vlasov–Fokker–Planck equation for electrons and the fluid equations for cold ions. These equations are solved using approximations which maintain good accuracy but allow faster computational solution than was previously possible. It is found that the spatial profiles for temperature and density in planar geometry differ very little from those calculated from the Spitzer conductivity. At high laser intensities, the plasma flow diverges as it flows away from the solid target and the effects of nonplanar flow are important. This is modeled by the adoption of spherical geometry, and it is found that the Spitzer conductivity breaks down and the temperature and density profiles differ significantly from those calculated using the Spitzer conductivity.