Application of Kinetic Theory to Study Twisted Modes in Non-Maxwellian Plasma

The orbital angular momentum states have been studied in the regime of Classical and Quantum Optics [1]. However, recently Mendonca et al. have predicted the theoretical foundations of intense Laser beam having orbital angular momentum state for Laser-Plasma interaction [2]. It exhibits paradigmatic alteration of Inverse Faraday’s effect [3]. The orbital angular momentum states are being studied for plasma vortices [4]. In this regard, Kinetic theory developed for the orbital angular momentum states [5, 6] is based on Maxwellian distribution of the plasma constituents. However, most of the Space Plasmas and some of the Laboratory Plasmas exhibit non-thermal/non-Maxwellian behavior [7] due to spatial variation of number density, temperature, magnetic field intensity and background turbulence. In this regard, it would be very interesting if we can develop a kinetic theory that can help us in understanding the effect of orbital angular momentum part of the waves on these non-thermal plasma systems.

In our research work we will develop a Kinetic Theory based model for studying non-Maxwellian/non-thermal plasmas in the presence of orbital angular momentum (OAM) states. We will use this theory to study the stability of plasma waves and vortices in the presence and absence of ambient magnetic field. For this purpose the Laguerre-Gaussian (LG) mode function will be employed to model the modified non-Maxwellian dielectric function for the study of wave particle interaction. The solutions will be obtained analytically and their validity will be verified by comparison with the numerical solution of the dispersion relation and stability parameter for the OAM oriented plasma modes. In our research work, we will present the non-Maxwellian/non-thermal OAM Kinetic Model using three dimensional Generalized Lorentzian/kappa (non-Maxwellian) distribution functions. The reason of selecting kappa or Generalized distribution function is its flexibility that we can also extract thermal effects for the large values of spectral indices.

[1] J. D. Jackson, “Classical Electrodynamics”, 2nd ed., Wiley New York ( 1962).

[2] J. T. Mendonca, B. Thide and H. Then, “Stimulated Raman and Brillouin backscattering of collimated beams carrying orbital angular momentum”, Phys. Rev. Lett. 102, 185005 (2009).

[3] S. Ali, J. R. Davies and J. T. Mendonca,”Inverse Faraday effect with linearly polarized laser pulses”, Phys. Rev. Lett. 105, 035001 (2010).

[4] J. T. Mendonca, S. Ali and B. Thide,”Plasmons with orbital angular momentum”, Phys. Plasmas 16, 112103 (2009).

[5] J. T. Mendonca, “Kinetic description of electron plasma waves with orbital angular momentum”,Phys. Plasmas 19, 112113 (2012).

[6] S. A. Khan, Aman-ur-Rehman and J. T. Mendonca,”Kinetic study of ion-acoustic plasma vortices”, Phys. Plasmas 21, 092109 (2014).

[7] Kashif Arshad, Zahida Ehsan, S. A. Khan and S. Mahmood,”Solar wind driven dust acoustic instability with Lorentzian kappa distribution ”, Phys. Plasmas 21, 023704 (2014).