Inertial Kinetic-Alfven Turbulence in a Space Plasma

Observations and analytical models indicate that the electron plasma beta parameter (ratio of the thermal to magnetic energy) becomes relatively small at low heliospheric distances, in the regions close to the solar corona, β_e << β_i ≤ 1. In such a regime, which is also encountered in the Earth’s magnetosheath and other astrophysical systems, kinetic-scale turbulence may be governed by the so-called inertial kinetic-Alfven modes [1,2]. We discuss the properties of this new regime of nonlinear plasma dynamics, present a phenomenological model of inertial kinetic-Alfven turbulence, and demonstrate that the results are in good agreement with the recent kinetic numerical simulations [3].

[1] Chen, C. H. K. & Boldyrev, S. Astrophys. J. 842 (2017) 122;

[2] Passot, T., Sulem, P. L., Tassi, E., Phys. Plasmas 25 (2018) 045107;

[3] Roytershteyn, V., Boldyrev, S., Delzanno, G. L., Chen, C. H. K., Grošelj, D., and Loureiro, N. F., Astrophys. J., 2018 (submitted).