title: Dynamics of self-trapped singular beams in an underdense plasma.
abstract: Dynamics of an intense short laser pulse with a phase singularity, propagating in an underdense cold plasma, is investigated. Such a pulse can propagate as a vortex soliton in a self-created channel. It is shown that vortices with the topological charge m=1,2 (and a corresponding angular momentum) are unstable against symmetry-breaking perturbations; the breakup of the original vortex leads to the formation of stable spatial solitons that steadily fly away tangentially from the initial ring of vortex distribution.
authors: Graduate School of Frontier Sciences, The University of Tokyo, Hongo 7-3-1, Tokyo 113-0033, Japan.
authors: V I
authors: VI
authors: Berezhiani
authors: S M
authors: SM
authors: Mahajan
authors: Z
authors: Z
authors: Yoshida
authors: M
authors: M
authors: Pekker