Global Theory of Microtearing Modes in the Tokamak Pedestal.

The pedestal of H-mode tokamaks displays strong magnetic fluctuations correlated with the evolution of the electron temperature. The microtearing mode (MTM), a temperature-gradient-driven instability that alters magnetic topology, is compatible with these observations. Here we extend the conventional theory of the MTM to include the global variation of the temperature and density profiles.

Relativistic Plasma Polarizer: Impact of Temperature Anisotropy on Relativistic Transparency.

3D particle-in-cell simulations demonstrate that the enhanced transparency of a relativistically hot plasma is sensitive to how the energy is partitioned between different degrees of freedom. For an anisotropic electron distribution, propagation characteristics, like the critical density, will depend on the polarization of the electromagnetic wave. Despite the onset of the Weibel instability in such plasmas, the anisotropy can persist long enough to affect laser propagation.

Two-fluid temperature-dependent relativistic waves in magnetized streaming pair plasmas.

A relativistic two-fluid temperature-dependent approach for a streaming magnetized pair plasma is considered. Such a scenario corresponds to secondary plasmas created at the polar caps of pulsar magnetospheres. In the model the generalized vorticity rather than the magnetic field is frozen into the fluid.

Plasma fluctuations as Markovian noise.

Noise theory is used to study the correlations of stationary Markovian fluctuations that are homogeneous and isotropic in space. The relaxation of the fluctuations is modeled by the diffusion equation. The spatial correlations of random fluctuations are modeled by the exponential decay.

Applications of noise theory to plasma fluctuations.

Noise theory is used to study the temporal correlations of stationary random fluctuations that are homogeneous in space. Statistical properties of the fluctuations, such as the power spectrum and the correlation function, are computed. The results are compared with the observed plasma density fluctuations from tokamak experiments.

Topology of plasma equilibria and the current closure condition.

A virtually complete description of the topology of stationary incompressible Euler flows and the magnetic field satisfying the magnetostatic equation is given by a theorem due to Arnol'd. We apply this theorem to describe the topology of stationary states of plasmas with significant fluid flow, obeying the Hall magnetohydrodynamics model equations. In the context of the integrability (nonchaotic topology) of the magnetic and velocity fields, we discuss the validity of conditions analogous to that of Greene and Johnson, which, in the case of magnetostatic equations, states that the line integral dl/B is the same for each closed magnetic field line on a given magnetic surface.

Radiation reaction in fusion plasmas.

The effects of a radiation reaction on thermal electrons in a magnetically confined plasma, with parameters typical of planned burning plasma experiments, are studied. A fully relativistic kinetic equation that includes the radiation reaction is derived. The associated rate of phase-space contraction is computed and the relative importance of the radiation reaction in phase space is estimated.

Closed fluid description of relativistic, magnetized plasma interacting with radiation field.

A closed set of averaged fluid equations for a relativistic plasma immersed, simultaneously, in a slowly varying magnetizing field and a sharply varying electromagnetic field (radiation field, for example) of arbitrary intensity is derived. The modifications due to the radiation field on the plasma stress tensor and the Lorentz force are explicitly displayed. The resulting equations include the effects of radiation reaction as well as radiation pressure.

Radiation reaction and relativistic hydrodynamics.

By invoking the radiation reaction force, first perturbatively derived by Landau and Lifschitz, and later shown by Rohrlich to be exact for a single particle, we construct a set of fluid equations obeyed by a relativistic plasma interacting with the radiation field. After showing that this approach reproduces the known results for a locally Maxwellian plasma, we derive and display the basic dynamical equations for a general magnetized plasma in which the radiation reaction force augments the direct Lorentz force.