THE DETERMINATION OF SPATIALLY NONUNIFORM ELECTRON DENSITY DISTRIBUTION,
Abstract
Electron densities were measured in the subsonic portion of a free-expansion argon jet by microwave and Langmuir probe methods. The electron density in the jet had a Gaussian radial distribution; along the axis of the jet the density fell off approximately exponentially. Microwave measurements were made by traversing the microwave beam across the jet. This allowed the spatial variation of electron density to be determined. The data were analysed with a ray-tracing technique. Langmuir probe measurements were made with cylindrical and flat probes under essentially collision free conditions and over a range of probe radius to Debye length ratios of about 10 to 50. Both electron and ion collection were measured and analysed. The electroncurrent part of the characteristic has, in the past, been interpreted in two different ways. These are the so-called 'deviation-from-linearity' method, and the 'two-tangentintercept' method. For a probe in free-molecular flow, electron densities determined by these methods (for the type of plasma under consideration and ideal probe characteristics) should not differ by more than about 30 percent. It was found, however, that the latter method gave values two or three times higher than the former method. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1965
- Accession Number
- AD0616614
Entities
People
- Kurt A. Graf
Organizations
- University of Toronto