Dissipation of Currents in Ionized Media

TLDR

The study analyzes how instabilities destroy electron drifts. Numerical calculations show that nonlinear turbulent flow randomizes the initial drift energy. Fastest stable drift energy (~0.9 kT) dissipates into instabilities within ~30 plasma periods, local disturbances grow without propagation, turbulent nonlinear flow randomizes drift energy, and runaway stops after ~100 plasma periods, leading to heating by collective collisions.

Abstract

The destruction of electron drifts by instabilities is analyzed. The fastest stable drift is calculated (drift energy $0.9kT$) and the energy of a faster drift is found to be dissipated into instabilities within, typically, 30 plasma periods. The growth of a local disturbance in this process is shown to take place without effective propagation. The "turbulent" flow pattern created, eventually, under nonlinear conditions is calculated numerically, demonstrating the tendency towards randomization of the initial drift energy. The effect stops "runaway" in about 100 plasma periods after which there is "heating" by "collective collisions" instead.