Dynamics of a high-density plasma in a magnetic field

TL;DR

This paper investigates how high-density plasma dynamics in a magnetic field influence plasma asymmetry and the ignition of new emission cells, with velocity estimates aligning with experimental observations.

Contribution

It introduces a model of plasma behavior in magnetic fields, highlighting asymmetry effects and estimating the velocity of plasma spot motion.

Findings

Plasma expansion causes asymmetry in density distribution.

Asymmetry increases likelihood of new cell ignition in stronger magnetic regions.

Estimated velocities of plasma spot motion match experimental data.

Abstract

The paper considers the dynamics of the plasma generated by the explosive-emission cells of the cathode spot of a vacuum arc in a magnetic field. It is shown that the expansion of the (high-density) plasma in a transverse magnetic field may cause asymmetry in the plasma density distribution at the cathode spot boundary. The asymmetry, in turn, increases the probability of the ignition of new explosive-emission cells in the region of a stronger magnetic field in the 'anti-amperian' direction of BxI. The disturbed plasma density distribution estimated in the MHD approximation is presented. In addition, the velocity of the 'retrograde' spot motion (ignition of new explosive-emission cells) in the stronger field region is estimated as a function of the external magnetic field strength. The velocity estimates (a few to tens of m/(s T)) are shown to agree with experimental data