Suppression of bremsstrahlung losses from relativistic plasma with energy cutoff.

We study the effects of redistributing superthermal electrons on bremsstrahlung radiation from hot relativistic plasma. We consider thermal and nonthermal distribution of electrons with an energy cutoff in the phase space and explore the impact of the energy cutoff on bremsstrahlung losses. We discover that the redistribution of the superthermal electrons into lower energies reduces radiative losses, which is in contrast to nonrelativistic plasma.

Multiphase nonlinear electron plasma waves.

We present a method for constructing multiphase excitations in the generally nonintegrable system of warm fluid equations describing plasma oscillations. It is based on autoresonant excitation of nonlinear electron plasma waves by phase locking with small amplitude chirped-frequency ponderomotive drives. We demonstrate the excitation of these multiphase waves by performing fully nonlinear numerical simulations of the fluid equations.

Holographic Plasma Lenses.

A hologram fully encodes a three-dimensional light field by imprinting the interference between the field and a reference beam in a recording medium. Here we show that two collinear pump lasers with different foci overlapped in a gas jet produce a holographic plasma lens capable of focusing or collimating a probe laser at intensities several orders-of-magnitude higher than the limits of a nonionized optic. We outline the theory of these diffractive plasma lenses and present simulations for two plasma mechanisms that allow their construction: spatially varying ionization and ponderomotively driven ion-density fluctuations.

Radiation in equilibrium with plasma and plasma effects on cosmic microwave background.

The spectrum of the radiation of a body in equilibrium is given by Planck's law. In plasma, however, waves below the plasma frequency cannot propagate; consequently, the equilibrium radiation inside plasma is necessarily different from the Planck spectrum. We derive, using three different approaches, the spectrum for the equilibrium radiation inside plasma.

Inverse Bremsstrahlung current drive.

The generation of the plasma current resulting from Bremsstrahlung absorption is considered. It is shown that the electric current is higher than the naive estimates assuming that electrons absorb only the photon momentum and using the Spitzer conductivity would suggest. The current enhancement is in part because electrons get the recoil momentum from the Coulomb field of ions during the absorption and in part because the electromagnetic power is absorbed asymmetrically within the electron velocity distribution space.