DC electric field generation and distribution in magnetized plasmas

TL;DR

This paper explores methods to generate and control large DC electric fields in magnetized plasmas using wave injection and neutral beams, overcoming traditional limitations imposed by metallic boundaries.

Contribution

It introduces novel techniques for sustaining large radial DC voltage drops in magnetized plasmas through wave and beam injection, with analysis of power balance and control parameters.

Findings

Large radial DC voltage drops can be sustained via wave injection.

Neutral particle beams can generate significant DC electric fields.

The distribution of voltage drops depends on plasma conductivity properties.

Abstract

Very large DC and AC electric fields cannot be sustained between conducting electrodes because of volume gas breakdown and/or surface field emission. However, very large potential fields are now routinely generated in plasma structures such as laser generated wake in unmagnetized plasmas. In magnetized plasmas, large DC fields can also be sustained and controlled perpendicular to the magnetic field, but the metallic end plates limiting the plasma, terminating the magnetic field lines and usually providing the voltage drop feed between the field lines, impose severe restrictions on the maximum field. However, it is shown that very large radial DC voltage drops can be sustained by injecting waves of predetermined frequencies and wave vectors, traveling along the azimuthal direction of an axially magnetized plasma cylinder, or by injecting fast neutral particles beams along this azimuthal direction. The large conductivity along the magnetic field lines and the small conductivity between the field lines then distribute this voltage drop. The global power balance and control parameters of wave and beam generated large DC electric fields in magnetized plasmas are identified, described and analyzed.