Laser plasma formation in metals vapour : kinetic approach

摘要

The break-down of metals vapour (Al, Cu) are simulated near the break-down threshold values of laser radiation. The approximations of collision-radiation model are used, including the detail kinetics of exited states with radiation and collision transitions, step-by-step ionisation process, unexitation and recombination. Energy balance is based on two-temperature approximation : for electrons and for heavy particles. It is shown that the particles concentration in exited states and plasma species composition differ rather from Saha-Boltzmann's distribution. Strong dependence of the break-down threshold intensity on initial temperature of neutral and charged particles is shown.