Numerical Study of Inertial Kinetic-Alfvén Turbulence

Abstract

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-Alfvén turbulence (iKAW), is relevant for the solar corona, Earth's magnetosheath, and other astrophysical systems where the electron and ion plasma beta parameters satisfy the condition β e ≪ β i ≲ 1. In this paper we present kinetic numerical simulations that confirm the existence of the iKAW regime. Specifically, the simulations demonstrate a transition at scales below electron inertial length d e when β e ≪ β i ≲ 1. Spectral slopes and other statistical properties of turbulence at sub-d e scales are consistent with the phenomenological theory of inertial kinetic-Alfvén turbulence proposed by Chen & Boldyrev (2017) and with the recent observations in the Earth's magnetosheath. ©2019