Cross-focusing of two co-axial Gaussian electromagnetic beams in a magnetoplasma and plasma wave generation

Abstract

Presents an investigation of the cross-focusing of two Gaussian electromagnetic beams (two-dimensional) and consequent plasma wave generation at difference frequency Delta omega (= omega 1 approximately omega 2; omega 1 and omega 2 being angular frequencies of the two pump waves) in a hot collisionless magnetoplasma. The two Gaussian EM beams are assumed to be propagating along the static magnetic field in the extraordinary mode. Because of Gaussian intensity distribution of the two EM beams ponderomotive force becomes finite and redistribution of the electrons occurs. If the initial powers of the two EM beams are more than the critical powers for self-focusing, the beams get self-focused. The fact that the ponderomotive force is dependent on the intensities of both the beams, leads to 'cross-focusing' i.e. focusing of one beam is affected by the other. Plasma wave generation at difference frequency which depends on the background electron density and effective intensity of the two beams gets accordingly modified. It is seen that the magnitude of the magnetic field considerably affects the plasma wave excitation.