Accession Number : AD0701442

Title :   PROPERTIES OF COLLISIONLESS PLASMAS.

Descriptive Note : Final rept.,

Corporate Author : AVCO EVERETT RESEARCH LAB EVERETT MASS

Personal Author(s) : Patrick,R. M.

Report Date : JAN 1970

Pagination or Media Count : 46

Abstract : A plasma wind tunnel was developed which, for the first time, created a steady flow (for times in excess of one millisecond) of collision-free plasma. This plasma has a transport-free path which is very long compared to the flow dimensions (one meter); however, the gyro radii of the ions and electrons in the flow are small compared to the flow dimension. This apparatus was used where the plasma flow pressure was large compared to the magnetic field in the plasma, allowing the study of flows where the plasma speed was greater than the local Alfven speed in the flow. This is necessary to study stationary shock structure, since a super-Alfvenic flow is required to produce plasma shock waves. A high pressure Magnetic Annular Arc (MAARC) facility was constructed to test the feasibility of increasing the stagnation pressure of an ultra-high-speed gas flow (velocities in excess of 25,000 ft/sec). The stagnation pressure in a nitrogen flow was increased from 2 atm to nearly 10 atm. This device operates at a power level equal to 20 million watts and has an anode bore equal to 5 cm, demonstrating the successful use of magnetic fields to control heat transfer and create useful body forces. The magnetic annular arc technology was also used to produce high speed shocks in a conventional shock tube. This was done using a standard 4-cm bore shock tube, and collisional shock waves with speeds in excess of 20,000 m/sec were obtained. (Author)

Descriptors :   (*WIND TUNNELS, *PLASMA MEDIUM), MAGNETIC FIELDS, ELECTRIC ARCS, SHOCK TUBES, PLASMA ACCELERATORS, STAGNATION POINT, PRESSURE

Subject Categories : Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE