Upper hybrid wave excitation and particle acceleration by resonant beating of two hollow Gaussian laser beams in magnetized plasma

Abstract

This paper investigates the excitation of the upper hybrid wave by resonant beating of two intense hollow Gaussian relativistic laser beams in a magnetized plasma. Hollow laser beams are taken in this study because they have the same power at different beam orders. The interaction of two intense hollow laser beams at the frequency difference ( Δ ω ≈ ω 1 − ω 2 ) and wavenumber ( Δ k = k 1 − k 2 ) excites the upper hybrid wave in the magnetized plasma. The excited upper hybrid wave accelerates the electrons to higher energies. The acceleration of electrons has also been studied. This study is carried out under a higher-order paraxial region, where the dielectric constant and the eikonal are expanded to the fourth power of the radial distance. Analytical expressions are obtained for the beam width parameter of the hollow Gaussian laser beams, the electric field of the upper hybrid wave, and the energy gain by the electrons. The effects of various laser and plasma parameters (such as beam order, plasma frequency, and electron cyclotron frequency) on the electric field of the upper hybrid wave and the energy gain of electrons have been explored. The results are compared with paraxial region and the Gaussian profile of laser beams. Numerical analysis has been performed for well-established laser and plasma parameters.