MEASUREMENT OF ELECTRON DENSITY BEHIND SHOCK WAVES BY free-MOLECULAR LANGMUIR PROBES.
Abstract
There exists a lack of experimental confirmation of the collisionless electrostatic probe theory for ratios of the probe radius to Debye length of order unit or less which corresponds to orbital-motion-limited current to the probe. These conditions are needed to fulfill the desirability of free molecular flow for many applications, e.g., a ballistic ranges. The paper describes the development and the experiments on a free molecular cylindrical probe in the region behind the incident shock wave to compare the measurements with collisionless probe theory. The measurements were made in an air/argon mixture with an initial pressure of 0.2 torr and a shock speed of 2.8 mm/microseconds resulting in temperatures of 7000K and electron densities up to 10 to the 12th power/cc far downstream of the shock wave. The probe radii were of the same order as the Debye length. The experimental results confirm the theoretical predictions for electron collection in the orbital-motion-limited regime. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1969
- Accession Number
- AD0700047
Entities
People
- R. E. Center