Enhanced Anomalous Electron Heating by Nonlinear Interaction of Plasma Wave–Aided Beat Wave of Two Identical Profile Laser Beams in Plasma with Density Ripple

In the present theoretical investigation, an analytical formalism for the resonant anomalous electron heating process is studied by considering the beat wave of two Hermite-cosh-Gaussian laser beams. As the two laser beams of slightly different angular frequencies interact nonlinearly, accountability of the beat wave generation process is taken into consideration. The plasma electrons exert a nonlinear force generated by the beating process of two laser beams with a beat wave frequency ω = ω1 – ω2 and beat wavenumber k = k1 – k2. This strong nonlinear ponderomotive force displaces the electrons with respect to the immobile ion and creates the space charge potential. Because of the excursion of electrons, the electrostatic space charge wave must be coupled to the laser beat wave. The aid of the electron plasma wave with the beat wave of laser beams contributes to the resonant heating rate of electrons. In the presence of a static magnetic field, Landau damping plays a crucial role in the excitation of the electron plasma wave. An analytical expression of the anomalous laser electron heating rate is derived by using these two laser beams. The analytical and graphical results indicate that the electron heating rate is significantly influenced by varying the laser beam parameters (beam decentered parameter, initial beam width, mode index, and field amplitude) and plasma medium parameters (amplitude of density ripple, electron cyclotron frequency, and electron-neutral collisional frequency). This resonant anomalous laser electron heating process possesses potential applicable in plasma fusion devices and soft-X-ray– generation processes.