Dynamics of an Electrical Discharge Initiated by a Powerful Femtosecond Laser Pulse in Atmospheric Pressure Air in Pre-Breakdown Fields

The dynamics of a discharge initiated by a high-power femtosecond laser pulse in air at atmospheric pressure in pre-breakdown fields is numerically simulated. The calculations are carried out within a 1-D axisymmetric model that describes the evolution of the radial profiles of the main parameters of the discharge under study. The model includes a system of reactions that determine gas heating and a detailed description of the kinetic processes in a given discharge, as well as a system of gas-dynamic equations to describe the expansion of the heated channel. The calculation results of the breakdown time of the discharge gap are consistent with the measurement data over the entire studied range of electric field strengths, E = 9-17 kV/cm. It is shown that one of the key factors determining the evolution of the parameters of a given discharge is the gas heating rate.