The ponderomotive self-focusing of nonparaxial laser beam via magnetized plasma

Abstract

The self-focusing of laser beam propagating through magnetized plasma is occurring under effect of nonlinear ponderomotive force. This study is done in collisionless nonlinear interaction between right circular polarized laser beam (RCP) and magnetized plasma taking in our account the nonparaxial ray theory. This study is depending on the nonlinear interaction between Deuterium fluoride (DF) pulsed laser beam with a magnetized hydrogen plasma. It is important to mention that the employed laser is a fundamental Gaussian mode (TEM00) operating at wavelength corresponding to the laser beam angular frequency. Each pulse carry out energy equaling to (30 mJ- 3J)  so the initial laser beam intensity may reach to about  which is consider a sufficient intensity for laser plasma nonlinear interactions in ponderomotive regime. The main aim of this study is to derive suitable differential equations to investigate the nonlinear behavior of nonparaxial laser beam inside magnetized plasma. The study is also aiming to understand the difference between the self-focusing of laser beam in both nonparaxial and paraxial regions. By designing appropriate Matlab programs, the final equations of nonparaxial laser beam self-focusing have been solved numerically. The initial diameter of laser beam is playing a significant role for the self-focusing behavior of laser beam. The numerical results explain that the nonparaxial laser beam is self-focused lower comparing with the paraxial laser beam. Depending upon ray's diffraction theory in geometric optics, one may conclude that the laser rays in the nonparaxial region have naturally greater chance to converge comparing with the laser rays in paraxial region.