Improved Analysis Techniques for Cylindrical and Spherical Double Probes (Preprint)
Abstract
A versatile double Langmuir probe technique has been developed by incorporating analytical fits to Laframboise's numerical results for ion current collection by biased electrodes of various sizes relative to the local electron Debye length. Application of these fits to the double probe circuit has produced a set of coupled equations that express the potential of each electrode relative to the plasma potential as well as the resulting probe current as a function of applied probe voltage. These equations can be readily solved via standard numerical techniques in order to infer electron temperature and plasma density from experimental data. Because this method self-consistently accounts for the effects of sheath expansion, it can be readily applied to low-temperature plasmas with a wide range of densities without a priori tailoring of probe dimensions to the expected electron Debye length. The presented approach has been successfully applied to experimental measurements obtained in the plume of a low-power Hall thruster.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 21, 2012
- Accession Number
- ADA570716
Entities
People
- Brian Beal
- Daniel C Brown
- Daron Bromaghim
- Joseph Blakely
- Lee J Johnson
Organizations
- Air Force Research Laboratory