Transition of plasma into a strongly-coupled state as a possible reason for anomalous resistance in active space experiments

Abstract

A well-known phenomenon in the experiments on plasma injection in space is an appearance of anomalous electric resistance, which is usually attributed to the plasma turbulence. As is shown in our study, there may be yet another reason for this effect, namely, transition of the plasma into a strongly-coupled state in the process of its adiabatic expansion in vacuum. Since the kinetic energy of plasma decreases more rapidly than Coulomb energy, most electrons turn out to be quasi-localized in the vicinity of nearby ions. As a result, the electric current can be transferred only by a relatively small part of electrons, corresponding to the high-energy tail of the distribution function. The concentration of free charge carriers, calculated in our study, turns out to be independent of the plasma temperature and determined only by its density. (This features are somewhat similar, from the formal point of view, to the properties of degenerate Fermi gas.)