Wave Generation by Bessel Polarized Laser Beam in Plasma Beat-Wave Accelerator

Abstract

The plasma beat-wave accelerator (PBWA) scheme is one of a number of methods for producing relativistic electron plasma waves via the interaction of an intense laser pulse with an underdense plasma. The PBWA scheme involves the co-propagation through a plasma of two laser pulses of slightly differing frequencies, ω 1 and ω 2 such that ( ω 1 − ω 2 = ω b ≪ ω 1 , ω 2 ). The superposition of these laser envelopes with which there is an associated ponderomotive force. If the frequency of the force is resonant with the electron plasma frequency ω p e , a large-amplitude relativistic electron plasma wave (EPW) can be produced. In our work, we have studied the direct acceleration of electrons by using crossed linearly polarized Bessel beams with slightly different frequencies in underdense plasma. General wave equation which describes the beat magnetic field has been obtained and analytically solved for any plasma density and beam frequency. The electric field of a longitudinal electron plasma oscillation with plasma velocity ( v p h ) near the speed of light ( c ) accelerates charged particle to high energies is presented. It is possible for radiation beat wave to resonantly drive large amplitude electron plasma waves. It is found that plasma waves are of particular interest can accelerate electrons efficiently to high energies with short distances. Such electrons may be used to address other therapies such as allowing for a handheld radiation therapy device that can directly target superficial skin cancers such as melanoma.