Jens Zamanian

Effects of the g factor in semiclassical kinetic plasma theory

A kinetic theory for spin plasmas is put forward, generalizing those of previous authors. In the model, the ordinary phase space is extended to include the spin degrees of freedom. Together with Maxwells equations, the system is shown to be energy conserving. Analyzing the linear properties, it is found that new types of wave-particle resonances are possible that depend directly on the anomalous magnetic moment of the electron. As a result, new wave modes, not present in the absence of spin, appear. The implications of our results are discussed.

Scalar quantum kinetic theory for spin-1/2 particles: mean field theory

Starting from the Pauli Hamiltonian operator, we derive scalar quantum kinetic equations for spin-1/2 systems. Here, the regular Wigner two-state matrix is replaced by a scalar distribution functio ...

Semi-relativistic effects in spin-1/2 quantum plasmas

Emerging possibilities for creating and studying novel plasma regimes, e. g. relativistic plasmas and dense systems, in a controlled laboratory environment also require new modeling tools for such ...

Short wavelength electromagnetic propagation in magnetized quantum plasmas

The quantum electrodynamical (QED) short wavelength correction on plasma wave propagation for a nonrelativistic quantum plasma is investigated. A general dispersion relation for a thermal multicomponent quantum plasma is derived. It is found that the classical dispersion relation for any wave mode can be modified to include quantum and short wavelength QED effects by simple substitutions of the thermal velocity and the plasma frequency. Furthermore, the dispersion relation has been modified to include QED effects of strong magnetic fields. It is found that strong magnetic fields together with the short wavelength QED correction will induce dispersion both in vacuum and in otherwise nondispersive plasma modes. Applications to laboratory and astrophysical systems are discussed.

From extended phase space dynamics to fluid theory

We derive a fluid theory for spin-1/2 particles starting from an extended kinetic model based on a spin-projected density matrix formalism. The evolution equation for the spin density is found to contain a pressurelike term. We give an example where this term is important by looking at a linear mode previously found in a spin kinetic model.

Fluid moment hierarchy equations derived from quantum kinetic theory

A set of quantum hydrodynamic equations are derived from the moments of the electrostatic mean-field Wigner kinetic equation. No assumptions are made on the particular local equilibrium or on the statistical ensemble wave functions. Quantum diffraction effects appear explicitly only in the transport equation for the heat flux triad, which is the third-order moment of the Wigner pseudo-distribution. The general linear dispersion relation is derived, from which a quantum modified Bohm–Gross relation is recovered in the long wave-length limit. Nonlinear, traveling wave solutions are numerically found in the one-dimensional case. The results shed light on the relation between quantum kinetic theory, the Bohm–de Broglie–Madelung eikonal approach, and quantum fluid transport around given equilibrium distribution functions.

Dynamics of a dusty plasma with intrinsic magnetization

We consider a dusty plasma where dust particles have a magnetic dipole moment. A Hall-MHD type of model, generalized to account for the intrinsic magnetization, is derived. The model is shown to be energy conserving, and the energy density and flux are derived. The general dispersion relation is then derived, and we show that kinetic dust-Alfven waves exhibit instability for a low dust and ion temperature and high dust density. We discuss the implication of our results.We consider a dusty plasma where the dust particles have a magnetic dipole moment. A HallMHD type of model, generalized to account for the intrinsic magnetization, is derived. The model is shown to be energy conserving, and the energy density and flux is derived. The general dispersion relation is then derived, and we show that kinetic Alfvén waves exhibit an instability for a low temperature and high density plasma. We discuss the implication of our results.

Fluid moment hierarchy equations derived from gauge invariant quantum kinetic theory

The gauge invariant electromagnetic Wigner equation is taken as the basis of a fluid-like system describing quantum plasmas, derived from the moments of the gauge invariant Wigner function. The use ...

Exchange effects in plasmas: The case of low-frequency dynamics

Recently, there has been a surge of interest in nonequilibrium collective quantum models, where particle dispersion and spin are examples of effects taken into account. Here, we derive a kinetic plasma model containing fermion exchange effects. Exchange interactions are of great importance in many systems and have no classical analogy. Our model therefore constitutes a possible probe of collective quantum phenomena in other regimes. As an example, we consider the influence of the exchange effect on low-frequency dynamics, in particular ion-acoustic waves. Comparisons to related computational techniques are given and the differences are highlighted. Furthermore, we discuss the applicability of our model, its limitations, and possible extensions.

Strong field effects in laser pulses : the Wigner formalism

We investigate strong field vacuum effects using a phase space approach based on the Wigner formalism. We calculate the Wigner function in a strong null-field background exactly, using lightfront f ...