Angular distribution of hot electrons incident on a laser-irradiated target

Angular distributions of bremsstrahlung emission are calculated for various energy and angular distributions of hot electrons incident on a laser-irradiated plastic target. These theoretical results are used to interpret experimental data of x-ray continuum emission from a CO2-laser-produced plasma. It is shown that at low irradiance (I/sub L/< or =5 x 1012 W/cm2) the incident electrons are normal to the target surface but that at higher irradiance, the incident electrons' angular distribution (spatially integrated over the target surface) is semi-isotropic. The influence of the directional distribution of hot electrons on axial energy transport is also studied by comparing calculated continuum x-ray spectra as well as energy-deposition profiles with experimental results