Numerical simulations of ultrashort laser pulse multifilamentation in fused silica: plasma channels statistics

The regime of multiple filamentation of gigawatt-power femtosecond laser pulses in fused silica bars is theoretically investigated. Numerical simulations are used to analyze the fine spatial structure of the plasma region formed due to photoionization of silica and accompanying pulse filamentation. The dependence of the number, spatial position, and length of different generations of plasma channels on the energy and focusing conditions of the optical pulse is studied. The role of pulse sequential refocusing in the formation of the plasma region is discussed. (paper)