Numerical study of the Transverse Diffusion coefficient for a one component model of a plasma

TL;DR

This study uses molecular dynamics simulations to explore how the transverse diffusion coefficient in a plasma varies with temperature and magnetic field, revealing threshold behaviors and deviations from classical predictions.

Contribution

It provides new insights into the temperature and magnetic field dependence of the transverse diffusion coefficient in a plasma, highlighting threshold effects and deviations from Bohm law.

Findings

Diffusion coefficient decreases with increasing temperature above a threshold.

Below the threshold, diffusion follows Bohm law $D_{ot} \\sim T/B$.

At high magnetic fields, diffusion saturates instead of decreasing indefinitely.

Abstract

We report the results of MD numerical simulations for a one component model of a plasma in the weakly coupled regime, at different values of temperature $T$ and applied magnetic field $\vec B$, in which the diffusion coefficient $D_{\perp}$ transverse to the field is estimated. We find that there exists a threshold in temperature, at which an inversion occurs, namely, for $T$ above the threshold the diffusion coefficient $D_{\perp}$ starts decreasing as $T$ increases. This is at variance with the behavior predicted by the Bohm law $D_{\perp}\sim T/B$, which actually holds below the threshold. In addition we find that, for temperatures above such a threshold, another transition occurs, now with respect to the values of the magnetic field: for weak magnetic fields the diffusion coefficients scales as $1/B^2$, in agreement with the predictions of the standard kinetics theory, while it apparently saturates when the field strength is sufficiently increased.