Numerical Study of Inertial Kinetic-Alfven Turbulence

Recent observational and analytical studies suggested that a new regime of kinetic turbulence may exist in plasma environments with low electron beta (Chen & Boldyrev 2017). Such a regime, termed inertial kinetic-Alfven turbulence, is relevant for the solar corona, Earth's magnetosheath, and other astrophysical systems where the electron and ion plasma beta parameters satisfy the condition βe ≪ βi ≲ 1. In this paper we present kinetic numerical simulations that confirm existence of the iKAW regime. Specifically, the simulations demonstrate a transition at scales below electron inertial length de when βe ≪ βi ≲ 1. Spectral slopes and other statistical properties of turbulence at sub-de scales are consistent with the phenomenological theory of inertial kinetic-Alfven turbulence proposed by Chen & Boldyrev (2017) and with the recent observations in the Earth's magnetosheath.