Nonequilibrium processes accompanying expansion of a high-temperature plasma bunch

An investigation is made of ionization level relaxation accompanying expansion of a high-temperature aluminum plasma bunch. A numerical scheme is proposed for solving a system of equations describing the whole range of kinetic processes in a two-temperature plasma. An analysis is made of the influence of expansion and of the Doppler frequency shift on the transport of resonant radiation and an analytic expression is obtained for the probability of escape of quanta from the plasma volume. The space-time behavior of the density, electron and ion temperatures, degree of ionization, and level population is obtained for expansion of a plasma bunch having an initial specific input energy of 10⁹ J/g. An inversion is predicted for populations of various levels (between Al XII and Al II depending on the plasma mass). An analysis is made of the feasibility of lasing as a result of resonant scattering due to an amplifying transition.