arXiv subjects

K. Morawetz

Publications and source records attributed to K. Morawetz.

58 records · Page 4Linked to original sources

arXiv1997

Debye-Onsager-Relaxation-Effect beyond linear Response and Antiscreening in Plasma Systems

The quantum kinetic equation for charged particles in strong electric fields is derived and analyzed with respect to the particle flux. It is found that the applied electric field is screened nonlinearly. The relaxation field is calculated completely quantum mechanically and up to any order in the applied field. The classical limit is given in analytical form. In the range of weak fields the deformation of the screening cloud is responsible for the Debye-Onsager relaxation effect. The result beyond linear response presented here allows to investigate a field regime where no screening cloud is present. The descreening field is determined as a function of thermal energy density of the plasma. For stronger fields the moving charge is accelerated by accumulated opposite charges in front of the particle. This can be understood in analogue to the accoustic Doppler effect. A critical field strength is presented up to which value a thermalized plasma is possible. The range of applicability of the treatment is discussed with respect to applied field strength and space gradients.

cond-mat.stat-mech↗

arXiv1997

Exact Solution of selfconsistent Vlasov equation

An analytical solution of the selfconsistent Vlasov equation is presented. The time evolution is entirely determined by the initial distribution function. The largest Lyapunov exponent is calculated analytically. For special parameters of the model potential positive Lyapunov exponent is possible. This model may serve as a check for numerical codes solving selfconsistent Vlasov equations. The here presented method is also applicable for any system with analytical solution of the Hamilton equation for the formfactor of the potential.

physics.plasm-ph↗

arXiv1996

In-medium two-nucleon properties in high electric fields

The quantum mechanical two - particle problem is considered in hot dense nuclear matter under the influence of a strong electric field such as the field of the residual nucleus in heavy - ion reactions. A generalized Galitskii-Bethe-Salpeter equation is derived and solved which includes retardation and field effects. Compared with the in-medium properties in the zero-field case, bound states are turned into resonances and the scattering phase shifts are modified. Four effects are observed due to the applied field: (i) A suppression of the Pauli-blocking below nuclear matter densities, (ii) the onset of pairing occurs already at higher temperatures due to the field, (iii) a field dependent finite lifetime of deuterons and (iv) the imaginary part of the quasiparticle self-energy changes its sign for special values of density and temperatures indicating a phase instability. The latter effect may influence the fragmentation processes. The lifetime of deuterons in a strong Coulomb field is given explicitly.

cond-mat↗

arXiv1993

In-medium relativistic kinetic theory and nucleon-meson systems

Within the $σ-ω$ model of coupled nucleon-meson systems, a generalized relativistic Lenard--Balescu--equation is presented resulting from a relativistic random phase approximation (RRPA). This provides a systematic derivation of relativistic transport equations in the frame of nonequilibrium Green's function technique including medium effects as well as fluctuation effects. It contains all possible processes due to one meson exchange and special attention is kept to the off--shell character of the particles. As a new feature of many particle effects, processes are possible which can be interpreted as particle creation and annihilation due to in-medium one meson exchange. In-medium cross sections are obtained from the generalized derivation of collision integrals, which possess complete crossing symmetries.

nucl-th↗