A. A. Valuev

Superheating of solid metal prior to electric explosion of wires at fast energy deposition

We develop the concept which distinguishes the initial stages of the fast (nanosecond) electric explosion of wires: the superheating of the solid conductor, its spontaneous (spinodal) decay and the successive formation of the non-ideal plasma column. We use the molecular dynamics simulation approach to simulate homogeneous nucleation from a stationary state and at a constant heating rate. We study the parameters of the spinodal, the dependence of the melting temperature on the heating rate and the character of the decay. We consider the subsequent evolution of the fluid column and the axial plasma uniformity. We compare the results with the experimental data on nanosecond wire explosions.

Nonideal plasmas as non-equilibrium media

Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential stage of the relaxation process are studied for a wide range of ion charge, nonideality parameter and ion mass. A simulation model of the nonideal plasma excited by an electron beam is proposed. An approach is developed to calculate the dynamic structure factor in non-stationary conditions. Instability increment is obtained from MD simulations.

Anomalous reflectivity from nonideal plasma

An approach is developed for computation of the reflectivity from nonideal plasma for probe laser frequencies ω near the plasma frequency ωp. Different factors are taken into account which could violate the conventional Drude dependence of the reflectivity on the ω/ωp ratio. Possible nonequilibrium of experimental nonideal plasma appears to be the main factor.