Effect of Ion Mass and Charge State on Transport Vacuum Arc Plasmas Through a Biased Magnetic Filter

Publication Type

Journal Article

Date Published

04/2004

LBNL Report Number

LBNL-53728

Abstract

The effect of ion mass and charge state on plasma transport through a 90 deg.-curved magnetic filter is experimentally investigated using a pulsed cathodic arc source. Graphite, copper, and tungsten were selected as test materials. The filter was a bent copper coil biased via the voltage drop across a low-ohm, selfbias resistor. Ion transport is accomplished via a guiding electric field, whose potential forms a trough shaped by the magnetic guiding field of the filter coil. Evaluation was done by measuring the filtered ion current and determination of the particle system coefficient, which can be defined as the ratio of filtered ion current, divided by the mean ion charge state, to the arc current. It was found that the ion current and particle system coefficient decreased as the mass-to-charge ratio of ions increased. This result can be qualitatively interpreted by a very simple model of ion transport that is based on compensation of the centrifugal force by the electric force associated with the guiding potential trough.

Journal

IEEE Transactions on Plasma Science

Volume

32

Year of Publication

2004

Pagination

433-439
433

Issue

2

ISSN

0093-3813

Accession Number

8051531