Quasi-steady expansion of plasma ablated from laser-irradiated pellets

The ablative, quasi-steady expansion of the spherical coronal plasma produced by irradiating an overdense pellet by a high-intensity laser pulse, is studied for large ion charge number Zi. The entire structure of the flow and its changes as the laser power is increased, are determined. The instantaneous power W required to generate a given ablation pressure Pa and pellet radius ra at any time is determined in terms of Zi, ion mass mi, and critical density; the mass ablation rate is also found. If the time law Pa(t) and (consequently) ra(t) for a desired optimal compression of the pellet are determined independently, the results allow one to obtain the laser power history W(t) = W[Pa(t), ra(t), Zi, mi, nc]. For a critical radius much larger than ra, most of the energy flows outward; this seems to invalidate known simple estimates of the relation W(Pa).