The three-fluid generalized Ohm's law: A theoretical study

Abstract

The two-fluid generalized Ohm's law (GOL) is based on the assumption that plasma is composed of only protons and electrons. The three-fluid GOL is obtained theoretically for the three-fluid plasma consisting of heavy ions, light ions, and electrons, which prevails in planetary ionospheres and magnetospheres. Three inertial lengths corresponding to the three-scale diffusion region in the three-fluid magnetic reconnection are derived. The ion inertial lengths and reconnection rate as well as the Hall magnetic and electric fields are modified due to the two-step decoupling process of ions. Our results provide a framework to extend the reconnection theory for even more ion species.