EXPERIMENTAL INVESTIGATION OF COLLISION-FREE SHOCKS AND PLASMAS. Research Report No. 122

Technical Report · Fri Sep 01 04:00:00 EDT 1961

OSTI ID:4782979

Patrick, R M; Camac, M

Investigation of the structure of a shock wave provides an excellent opportunity for studying the dissipation processes in collision-free plasmas. The thickness of collision-free shock waves was previously obtained from measurements of the light emitted by the plasma in a magnetic annular shock tube. The magnitude of the shock thickness, and its Mach number and density dependence were in agreement with a theoretical estimate based on the concept that the required dissipation in the shock is produced by nonlinear interactions between magnetohydrodynamic waves. Further confirmation of these results was obtained. Measurements of the magnetic field showed that the magnitude of the field change across the shock agrees with that expected from the conservation equations. Also the distance over which the field changes agrees with the previous shock thickness measurements. The electron temperature was estimated to be above 10 ev based on the ultraviolet radiation intensity and the ratio of bound-bound and free-free radiation. Measurements of the heat transfer from the plasma to the shock tube wall indicates that less than 1/10 of the gas energy is dissipated to the walls; thus, there is good containment of the shock heated plasma for a time large (50 times) compared to the shock rise transit time. The results of these experiments show that the collision-free thickness is inversely proportional to the Alfven Mach number of the shock. The radiation emitted by the shock heated plasma was measured over a large range in plasma density; these results, together with those for the magnetic field jump across the shock, show that the performance of the magnetic annular shock tube can be predicted by a theory which assumes infinite plasma conductivity. (auth)

• Research Organization: Avco Corp. Avco-Everett Research Lab., Everett, Mass.
• NSA Number: NSA-16-015716
• OSTI ID: 4782979
• Report Number(s): AFOSR-2266
• Country of Publication: United States
• Language: English

Related Subjects

ALFVEN WAVES
CONFIGURATION
CONFINEMENT
CONTAINMENT TIME
DENSITY
DISTRIBUTION
ELECTRIC CONDUCTIVITY
ELECTRONS
EMISSION
ENERGY
EV RANGE
GASES
HEAT TRANSFER
HYDROMAGNETIC WAVES
INTERACTIONS
LIGHT
MACH NUMBER
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICS
MEASURED VALUES
NONLINEAR PROBLEMS
OSCILLATIONS
PERFORMANCE
PHYSICS
PLASMA
PLASMA WAVES
SHOCK WAVES
SURFACES
TEMPERATURE
THERMONUCLEAR REACTIONS
THICKNESS
TORUS
TUBES
ULTRAVIOLET RADIATION
VARIATIONS
VELOCITY
VESSELS