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An experimental research on the interaction between a plasma flow and a magnetic field with nozzle-shaped lines of force was made with a large electron Hall parameter. The experiment was made using the plasma flow from a dc arc discharge and a magnetic field generated by a current loop. Measurements were made of the radiation emerging from the plasma flow, the number density of ions, the electron temperature, the impact pressure and the velocity of ions. The results showed that by the application of the magnetic field, the flow was strongly channelled and the electric field was induced in the flow. A theoretical analysis was made to explain the experimental results, using the gasdynamic equations, the generalized Ohm's law and the Maxwell's equations. The theoretical results explained very well the mechanism of the interaction occuring upstream of the coil. The plasma flow was found to flow along magnetic lines of force. The magnetic nozzle, however, accelerated the ions to a higher velocity than that expected from the isentropic expansion., 資料番号: SA2400783000

The interaction between a plasma flow and the magnetic field produced by a ring coil was investigated experimentally in order to confirm the channelling effect of the magnetic field. The plasma flow was produced in a quartz tube by an arc jet. Before imposing the magnetic field on the plasma flow, the flow conditions such as temperature, velocity, and static pressure were measured. The results show that the flow conditions change only very slowly along the stream, and that the flow is either subsonic or supersonic, depending on the arc current. The distributions of the wall pressure and gas luminosity were calculated numerically by a linearized theory which assumes that there exists only a small effect of the magnetic field on the plasma flow, and which neglects the Hall effect and the charge separation. In the measurements of the wall pressure distribution, a remarkable contrast between the case of a subsonic and a supersonic flow was observed, just as is predicted by the linearized theory. From the photographic observations and from the gas luminosity measurements, it was found for both the subsonic and supersonic flow cases that the plasma density decreases near the wall of the quartz tube at locations downstream of the ring coil. This result has been explained theoretically. Thus, the magnetic channelling effect of a ring coil on the plasma flow was clearly demonstrated., 資料番号: SA2404914000

An arc-heated plasma flow was produced in a glass pipe. The flow can be regarded as being approximately one-dimensional. It was found to be subsonic or supersonic, depending on the arc current. The preliminary studies, measurements of the temperature, velocity and static pressure, and calculations of the electrical and thermo-dynamical properties, were made. Owing to the wide interest in certain practical applications of the magnetic channelling effect and the magnetic piston, the magnetic field produced by a ring coil was selected to interact with the plasma flow. A linearized theory which assumes small changes in electrical and flow variables, and which neglects Hall effects and charge separation, was claculated for the variation of the wall pressure and gas luminosity to be compared witd the experimental results. The experimental results were in good agreement with those of frozen flow theory. A remarkable contrast was observed between a subsonic and a supersonic flows, just as predicted by the linearized theory. The magnetic channelling effect was recognized near the wall of the channel., 資料番号: SA4135089000