Propagation and stability of intense laser pulses in partially stripped plasmas

The propagation and stability of intense laser pulses in a partially stripped plasma, i.e., in the presence of free and bound electrons, is analyzed. The presence of bound electrons is shown to significantly alter the propagation and stability of intense laser pulses. The bound electrons are represented by a linear and nonlinear susceptibility, while the free electrons, which can support plasma waves, are treated nonlinearly. In the presence of both free and bound electrons, an atomic modulation instability develops that can have a growth rate substantially higher than either the conventional relativistic modulational instability or the forward Raman instability. Bound electrons can also greatly enhance the filamentation instability. The backward Raman instability, however, is unaffected by bound electrons.