Filamentation of a relativistic short pulse laser in a plasma

An intense short pulse laser propagating through a plasma undergoes filamentation instability under the combined effects of relativistic mass variation and ponderomotive force-induced electron density depression. These two nonlinearities superimpose each other. In a tenuous plasma, the filament size scales as where ω p is the plasma frequency, a 0 is the normalized laser amplitude and γ 0 is the relativistic gamma factor.