Stabilization of relativistic self-focusing of intense subpicosecond ultraviolet pulses in plasmas

The characteristcs of relativistic propagation in plasmas of subpicosecond ultraviolet (248-nm) radiation are studied for both spatially homogeneous plasmas and plasma columns. It is established for the first time that the defocusing properties of the interaction can represent a dynamical mechanism stabilizing the mode of propagation against radial oscillations. The dependence of both quasistabilized modes and pulsing waveguide regimes on the initial transverse intensity distribution is examined and, for the latter, the locus of the first focus produced in a homogeneous plasma is calculated.