Relativistic Propagation of Linearly/Circularly Polarized Laser Radiation in Plasmas

Abstract

Paraxial theory of relativistic self-focusing of Gaussian laser beams in plasmas for arbitrary magnitude of intensity of the beam has been presented in this paper. The nonlinearity in the dielectric constant arises on account of relativistic variation of mass. An appropriate expression for the nonlinear dielectric constant has been used to study laser beam propagation for linearly/circularly polarized wave. The variation of beamwidth parameter with distance of propagation, self-trapping condition, and critical power has been evaluated. The saturating nature of nonlinearity yields two values of critical power of the beam ( cr1 and cr2 ) for self-focusing. When < cr1 < cr2 the beam diverges. When cr1 < < cr2 the beam first converges then diverges and so on. When > cr2 the beam first diverges and then converges and so on. Numerical estimates are made for linearly/circularly polarized wave applicable for typical values of relativistic laser-plasma interaction process in underdense and overdense plasmas. Since the relativistic mechanism is instantaneous, this theory is applicable to understanding of self-focusing of laser pulses.

Generation of high-charge electron beam in a subcritical-density plasma through laser pulse self-trapping

“…We also comment regarding the effect of the polarization of laser light [21, p. 37] (see also [23]). For a linearly polarized laser wave, the value of a 0 in the relativistic gamma-factor expression should be replaced with a 0 / √ 2.…”

Bright synchrotron radiation from relativistic self-trapping of a short laser pulse in near-critical density plasma

“…The condition, Eq. ( 1), corresponds to the self-trapping regime of relativistic self-focusing (see, for example, [22,23]), which occurs for the laser pulses with the focal radius at the plasma entrance being close to the self-consistent radius. The initial laser pulse radius approaching the value Eq.…”