2D Fokker-Planck simulations of short-pulse laser-plasma interactions

The Fokker-Planck equation for electrons in two spatial dimensions in the diffusive approximation is solved by the alternating direction implicit method. The ions are modeled hydrodynamically. We discuss simulations of short-pulse (3.4 psec) experiments at a wavelength of (1/4 μm. We find substantial departures from Spitzer heat flow in both magnitude and direction. As a result we find that, even for 10-μm-diam laser spots, the heat flow into the target is not strongly reduced by energy escaping along the target surface.