Measurements of Non-Maxwellian Electron Distribution Functions and Their Effect on Laser Heating.

Electron velocity distribution functions driven by inverse bremsstrahlung heating are measured to be non-Maxwellian using a novel angularly resolved Thomson-scattering instrument and the corresponding reduction of electrons at slow velocities results in a $\ensuremath{\sim}40%$ measured reduction in inverse bremsstrahlung absorption. The distribution functions are measured to be super-Gaussian in the bulk ($v/{v}_{th}l3$) and Maxwellian in the tail ($v/{v}_{th}g3$) when the laser heating rate dominates over the electron-electron thermalization rate. Simulations with the particle code quartz show the shape of the tail is dictated by the uniformity of the laser heating.