Theoretical models of metal at high energy densities:
A physical and mathematical model is proposed to describe fast electrophysical processes in metal under the influence of intense electron and laser fluxes of femto- and picosecond duration, as well as high-voltage electromagnetic pulses with picosecond front and duration less than 1 ns. The dynamics of slow perturbations are described in the hydrodynamic approximation, and the fast dynamics of quasi-static excitations (phonons and conduction electrons) in the framework of kinetic equations. The equations obtained in the approximation of one quasi-neutral conducting fluid are in good agreement with the equations previously obtained by other authors. A new wide-range expression for electrical conductivity in a strong electromagnetic field is obtained and analyzed.
The dynamics of electronic and phonon spectra, as well as the features of structural phase transitions and sodium melting depending on the pressure in the range of 0-100 GPa were studied. The electron and phonon spectra were calculated in the framework of density functional theory and linear response using the LmtART-7 software package, which implements the fully potential method of linear maftin orbitals (FP-LMTO). Using the Lindeman criterion and the calculated phonon spectrum, the sodium melting curve is constructed, which is in good agreement with the experiment. The features of the dynamics of electronic and phonon spectra in the region of the maximum of the melting curve are studied.
