Magnetic Field and Geometry Effects on Finding Plasma Potential with a Cylindrical Impedance Probe
Abstract
A recent rf technique for determining plasma potential, using an impedance probe is predicted to be independent of probe geometry, magnetic field, and orientation. We test this for a cylindrical probe used in recent studies aimed at finding both plasma potential and the electron distribution function, f(epsilon), in the absence of a magnetic field. In the presence of a magnetic field, electron plasma resonances seen by impedance probes are shifted to the upper hybrid frequency and measurements of n(e) using a probe of cylindrical geometry can be strongly affected by orientation. However, in this note we demonstrate that measurement of plasma potential is not. The technique is based on combined experimental and theoretical methods developed in the Charged Particle Physics Branch at the Naval Research Laboratory. Earlier references to our work describe determination of electron density, n(e), and the construction of f(epsilon) for the cylindrical impedance probe in the absence of a magnetic field. The method has general application to diverse areas of plasma investigations in the laboratory or in space plasma measurement application.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 02, 2012
- Accession Number
- ADA565465
Entities
People
- D. D. Blackwell
- D. N. Walker
- Richard F. Fernsler
- W. E. Amatucci
Organizations
- United States Naval Research Laboratory