Plasma flow velocity gage at high magnetic Reynolds number
Abstract
A plasma flow velocity gage based on the principle of a Faraday generator has been developed for use in a shock tube at extreme conditions of pressure, temperature, and flow velocity. Barium ferrite permanent magnets provided a magnetic field transverse to the plasma flow and orthogonal with a pair of brass electrodes mounted nearly flush with the shock tube wall. The output voltage measured at the electrodes was proportional to the axial plasma flow speed and provided a velocity-time history independent of the pressure, temperature and electrical conductivity in the plasma. A laboratory mock-up with a spring-driven aluminum rod was used to simulate the plasma flow for calibration of the averaged, or effective, magnetic field strength and to verify the linearity of gage output at high magnetic Reynolds number. The gage output was found to be linear with flow velocity, and hence unperturbed by eddy currents, at magnetic Reynolds number up to 8.2. The velocity gage has been used successfully to measure plasma flow speed at pressures up to 1 GPa, temperatures of 50 kK, and flow speeds of 28 km/s.
- Publication:
-
Shock Tubes and Waves
- Pub Date:
- 1980
- Bibcode:
- 1980stw..proc..242B
- Keywords:
-
- Flow Velocity;
- Magnetohydrodynamic Flow;
- Shock Tubes;
- Velocity Measurement;
- Calibrating;
- Electrodes;
- Faraday Effect;
- Magnetic Properties;
- Plasma Probes;
- Reynolds Number;
- Plasma Physics