Screened Coulomb potential in a flowing magnetized plasma

TL;DR

This paper calculates the electrostatic potential around a moving dust grain in a magnetized plasma, revealing how magnetic fields and ion flow speed influence the potential's shape and wakefield formation.

Contribution

It extends previous unmagnetized plasma models to include magnetic fields, ion temperature, and collisions, using a new computational code for efficient calculations.

Findings

Magnetization significantly alters the potential shape at subsonic speeds.

Magnetic fields suppress wakefields at supersonic ion flow.

Potential distribution varies qualitatively with Mach number and magnetization.

Abstract

The electrostatic potential of a moving dust grain in a complex plasma with magnetized ions is computed using linear response theory, thereby extending our previous work for unmagnetized plasmas [P. Ludwig et al., New J. Phys. 14, 053016 (2012)]. In addition to the magnetic field, our approach accounts for a finite ion temperature as well as ion-neutral collisions. Our recently introduced code \texttt{Kielstream} is used for an efficient calculation of the dust potential. Increasing the magnetization of the ions, we find that the shape of the potential crucially depends on the Mach number $M$. In the regime of subsonic ion flow ($M<1$), a strong magnetization gives rise to a potential distribution that is qualitatively different from the unmagnetized limit, while for $M>1$ the magnetic field effectively suppresses the plasma wakefield.