The self-guiding of radially asymmetric relativistically intense laser beams

The evolution of initially sufficiently asymmetric super-strong laser pulse propagating in underdense cold plasma is studied. The effects of the relativistic electron mass increase and the repelling of electrons by the ponderomotive force from the central regions of laser beam propagation are taken into account. The beams with spot sizes much smaller than the pulse length are investigated. The beam, as well as plasma, characteristic parameters are obtained in the overcritical propagation regime, ignoring ion motion when the pulse self-focusing, self-guiding and filamentation take place. The role of the striction effect in the electron cavitation and ion channel formation phenomena is investigated. It is shown that, for specific parameters, the strongly asymmetric beam transforms to a symmetric one and later propagates in the plasma for a long distance.