RELATIVISTIC SELF-FOCUSING OF LASER-BEAMS IN TIME-HARMONIC PLANE-WAVES - ARBITRARY INTENSITY

This paper presents a paraxial theory of relativistic self-focusing of a Gaussian laser beam in plasma for a time-harmonic plane wave at arb itrary beam intensity. Since the relativistic mechanism is instantaneo us, the theory is also applicable to self-focusing of laser pulses. Th e analysis leads to two values for the critical beam power for self-fo cusing, P(cr1) and P(cr2). When P < P(cr1) < P(cr2), the beam diverges . When P(cr1) < P < P(cr2), it first converges, then diverges. and so on. When P > P(cr2), it first diverges, then converges, and so on.