The effect of static external magnetic field on the nonlinear absorption of the S-polarised short laser pulse in collisional underdense plasma

Abstract

Inverse Bremsstrahlung absorption is a mechanism for generating heat in the inertial confinement fusion (ICF) process. To maximise the heat produced, it is desirable to investigate the possibilities for increasing the absorption rate through the inverse Bremsstrahlung process. It should be noted that some absorption mechanisms found for nanosecond long laser pulses also appear for ultrashort laser pulses. In this paper, the physics of absorption for S-polarised laser pulse and magnetised underdense plasma interaction in the presence of electrons ohmic heating and ponderomotive nonlinearities is analysed for both collisional isothermal and collisional non-isothermal magnetised plasmas. Here, we show that, in the presence of a static magnetic field, the absorption rate of the S-polarised laser pulse through interaction with underdense plasma can be increased intensively. In other words, by applying an external magnetic field, the laser pulse radiation will penetrate a region of greater plasma density compared to the case of non-magnetised plasma for the S-polarised absorption. It is remarkable that due to the heat of the plasma at the expanse of the wave energy in the case of the non-thermal, magnetised and collisional plasma, the absorption coefficient is increased intensively in comparison with the collisional plasma.