A kinetic theory for quantum many-particle systems in time-dependent electromagnetic fields is developed based on a gauge-invariant formulation. The resulting kinetic equation generalizes previous results to quantum systems and includes many-body effects. It is, in particular, applicable to the interaction of strong laser fields with dense correlated plasmas.

Temperature equilibration in dense, strongly coupled plasmas has been investigated without most of the usual simplifying assumptions. A quantum kinetic approach is used that accounts for strong electron-ion collisions through an exact T-matrix treatment of the scattering cross section using a screened interaction. Our results reveal the accuracy of the usual Spitzer formula for Coulomb logarithms larger than about three. Moreover, a simple model based on hyperbolic orbits yields surprisingly accurate results. We also have included equation of state effects to describe realistic plasmas.

In this paper, nonequilibrium properties of strongly coupled plasmas are considered. Usually, such problems are dealt with using Boltzmann– or Lenard–Balescu-type equations. However, for the application to strongly coupled plasmas, these equations exhibit several shortcomings. So, it is not possible (i), to describe the short time kinetics, (ii), to recover the correct (energy) conservation laws and thermodynamics, and, (iii), to account for the formation or destruction of bound states. Therefore, the kinetics of strongly coupled plasmas is considered starting from the Kadanoff–Baym equations, which are known to overcome the above limitations. This is demonstrated by a numerical solution of the two-time Kadanoff–Baym equations in second Born approximation. To be able to discuss approximations which are physically more interesting, it is advantageous to proceed to the time diagonal Kadanoff–Baym equations. In first order gradient expansion, generalizations of the Boltzmann and of the Lenard–Balescu kinetic equations are derived accounting for the bound state problem, too. Thus, the shortcomings (i)–(iii) mentioned above are overcome. Finally, the kinetic equations are applied to the problem of ionization kinetics.

A quantum kinetic approach for the energy relaxation in strongly coupled plasmas with different electron and ion temperatures is presented. Based on the density operator formalism, we derive a balance equation for the energies of electrons and ions connecting kinetic, correlation, and exchange energies with a quite general expression for the electron-ion energy-transfer rate. The latter is given in terms of the correlation function of density fluctuations which allows for a derivation of increasingly realistic approximation schemes including a coupled-mode expression. The equilibration of the contributions of the total energy including the species temperatures in dense hydrogen and beryllium relevant for inertial confinement fusion is investigated as an example.

An equation of state is derived on the basis of Green's function technique. The formation of bound states is accounted for and the possibility of phase transitions is discussed. The latter is of special interest if it is connected with the vanishing of bound states at high densities, it is then a Mott phase transition.

A quantum kinetic theory for correlated charged-particle systems in strong time-dependent electromagnetic fields is developed. Our approach is based on a systematic gauge-invariant nonequilibrium Green's functions formulation. Extending our previous analysis [I] we concentrate on the selfconsistent treatment of dynamical screening and electromagnetic fields which is applicable to arbitrary nonequilibrium situations. The resulting kinetic equation generalizes previous results to quantum plasmas with full dynamical screening and includes many-body effects. It is, in particular, applicable to the interaction of dense plasmas with strong electromagnetic fields, including laser fields and x-rays. Furthermore, results for the modification .of the plasma screening and the longitudinal field fluctuations due to the electromagnetic field are presented.

SummaryThe composition andiihe equation of state for a binary mixture of dense partially ionized hydrogen and helium are investigated on the basis of quantum statistical theory. Theoretical evidence for the existence of a hydrogen-like and helium-like plasma phase transition is found. Critical data for the phase transitions are given for the whole range of the mixing parameter.

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