Resonant absorption of laser energy in X-mode configuration of magnetised plasma

There are several well-known mechanisms for the absorption of EM energy into plasma. For the case of magnetised plasma, electron-cyclotron resonance heating, ion-cyclotron resonance heating have been widely studied in the context of plasma heating. We propose a mechanism which relies on the excitation of lower hybrid mode in the system.  It has been recently reported that with the application of an external magnetic field, it is possible to couple laser energy directly into ions via excitation of lower hybrid mode in plasma [1,2].  Our work further extends this and propose a new heating mechanism in X-mode configuration of laser plasma system. We will discuss lower hybrid resonance heating mechanism to couple laser energy directly into ions. Our proposed mechanism is a three-fold process, laser first excites compressional Alfven mode in plasma which converts into electrostatic mode at the lower hybrid resonance point. This electrostatic mode then couples its energy into ions via wave-particle interaction. We will also discuss the role of appropriate gradient for the proposed mechanism. This work can find application where high energy needs to be dumped at a specified location in plasma.

 

References:

[1] A. Vashistha, D. Mandal, A. Kumar, C. Shukla, and A. Das, “A new mechanism of direct coupling of laser energy to ions,” New Journal of Physics, vol. 22, p. 063023, jun 2020.

[2] A. Vashistha, D. Mandal, & A. Das (2021). Excitation of lower hybrid and magneto-sonic perturbations in laser plasma interaction. Nuclear Fusion, 61(2), 026016.