The self-focusing of laser beams in magnetoplasmas: the moment theory approach

Abstract

The self-focusing of electromagnetic waves in plasmas (both unmagnetised and magneto-active) has been studied by the moment theory approach. It is seen that the earlier method of studying the phenomenon by the paraxial ray approximation gives results very different from those in the present study. The divergence between the two theories is acute close to gyroresonance for a longitudinally propagating right-handed circularly polarised wave. The moment theory also shows that there is a critical power for self-focusing and no upper limit to the power that can be self-trapped. These conclusions are in qualitative agreement with those from the paraxial ray approach.