Diffusion of One-Component Plasma in a Magnetic Field - Molecular Dynamics Study

Abstract

Molecular dynamics calculations have been performed on a classical, 3-dimensional one-component plasma, subjected to a magnetic field, which is uniform and constant in magnitude and direction; various values of the plasma parameter and magnetic field strength were considered. The Ewald sum technique was used to deal with the long-range Coulomb force, while the effects of the magnetic field were incorporated using a recently developed algorithm. This algorithm takes into account the effects of the magnetic field exactly and thus is more accurate than ones used previously. The two diffusion coefficients D z and D x , respectively parallel and perpendicular to the magnetic field have been calculated. Both coefficients decrease as a function of the magnetic field strength, but they differ considerably, with D x always less than D z . A noticeable plateau is observed in the plots of the diffusion coefficients, especially for intermediate values of the plasma parameter. A simple theoretical model based on the generalized Langevin equation is presented; its results are in reasonable qualitative agreement with the values obtained from molecular dynamics.

Keywords:

• One-component Plasma
• Molecular Dynamics
• Diffusion
• Langevin Equation