Distributed absorption model for moderate to high laser powers

Abstract

An analytic model is presented of a planar plasma heated by moderate to high laser powers such as are used to drive fusion pellets. Unlike previous models, this model explicitly includes the temporal evolution of the heat conduction region. It is shown that previous steady-state models apply only to a narrow range of the parameters (laser energy flux and pulse width) used in laser pellet fusion. The new model is shown to agree with flux-limited hydrodynamics simulations. The model and hydrodynamic simulations for classical heat transport show that the mass ablation rate and ablation pressure are essentially independent of laser wavelength for parameters relevant to laser fusion.