Electron Bernstein wave aided cosh-Gaussian laser beam absorption in plasma

Abstract

In this paper, we investigate the electron Bernstein wave aided cosh-Gaussian laser beam absorption in a plasma with static magnetic field. The cosh-Gaussian laser beam has potential to couple with pre-existed electron Bernstein wave and the coupled wave has frequency ω1=ω0+ω and wave number k1=k0+k where ω0 and ω are the laser and electron Bernstein wave frequencies respectively and k0 and k are the wave numbers of laser and electron Bernstein wave respectively. The oscillatory velocity due to laser couples with the density perturbation due to electron Bernstein waves to produce nonlinear current density driving the electromagnetic sideband wave. An expression of absorption coefficient is analytically derived when the nonlinear current density is in phase with cosh-Gaussian laser field. The graphical discussion promises the more absorption in plasma by varying laser beam decentered parameter, beam width, laser frequency, electron cyclotron frequency, parameter b, and electron Bernstein wave frequency. The laser beam decentered parameter behaves as a very sensitive parameter. The absorption process is found to be very robust even for very small change in electron Bernstein wave frequency as compared with laser frequency. This tunable and efficient absorption theory might be applicable in heating of plasma.