Low frequency electromagnetic fluctuations in Kappa magnetized plasmas

Abstract

The present paper provides a theoretical approach for the evaluation of the low frequency spontaneously emitted electromagnetic (EM) fluctuations in Kappa magnetized plasmas, which include the kinetic Alfven, fast magnetosonic/whistler, kinetic slow mode, ion Bernstein cyclotron modes, and higher-order modes. The model predictions are consistent with particle-in-cell simulations. Effects of suprathermal particles on low frequency fluctuations are studied by varying the power index, either for ions (kappa(i)) or for electrons (kappa(e)). Computations for an arbitrary wave vector orientation and wave polarization provide the intensity of spontaneous emissions to be enhanced in the presence of suprathermal populations. These results strongly suggest that spontaneous fluctuations may significantly contribute to the EM fluctuations observed in space plasmas, where suprathermal Kappa distributed particles are ubiquitous.