Kinetics of laser plasma formation in metal vapour

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