PLASMA FLOW IN A MAGNETIC ANNULAR ARC NOZZLE

Technical Report · Sat Sep 01 04:00:00 EDT 1962

OSTI ID:4778618

Patrick, R M; Powers, W E

The performance characteristics of a magnetic amular arc were experimentally investigated. This configuration consists of two coaxial electrodes separated by an annular passage through which the plasma flows with a steady solenoidal magnetic field throughout the flow region. Initial tests at small magnetic Reynolds number in a constant area configuration demonstrated that the impedance of the magnetic annular arc can be increased by a factor of 25 with the application of an axial magnetic field between the coaxial electrodes. This increased impedance was shown to be due to Hall currents that flow around the annulus between the electrodes. In addition to plasma heating, the interaction between the plasma currents and the magnetic field produced directed energy comparable to the thermal energy. To exhibit thrust, a 10 deg half angle nozzle was added and surveys of the plasma properties taken at the nozzle exit are presented. A 50 deg half angle nozzle configuration was also studied in which most of the plasma currents flow in the expanding flow region. An effort was made to produce directed axial energy through the interaction of the circulating Hall currents and the radial component of the magnetic field. Argon plasma properties were obtained by survey measurements of stagnation pressure, the electric field variation throughout the plasma flow, the flow direction, and the axial velocity profile of the flow. The stagnation pressure in the steady plasma flow was measured with an impact probe, the flow angles with special yaw probes, and the local electric potential in the plasma was measured with a high impedance probe, The velocity was obtained by utilizing a mass flow probe. The results from the plasma flow measurements indicated that the flow in the wide angle nozzle is dominated by Hall currents. (auth)

• Research Organization: Avco Corp. Avco-Everett Research Lab., Everett, Mass.
• NSA Number: NSA-17-000959
• OSTI ID: 4778618
• Report Number(s): NP-12160; AMP-86
• Country of Publication: United States
• Language: English

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