STEADY-STATE MPD ARC THRUSTER WITH A PERMANENT MAGNET.

With a steady-state operating MPD arc thruster, the discharge current cannot be made as large as is possible with its quasisteady counterpart. As a result, the electromagnetic acceleration effect produced by the self-induced magnetic field is not as large as desired. One common approach to overcoming this drawback is to apply an external magnetic field to the discharge region by means of a solenoidal coil. The resulting Lorentz force produced by the discharge current and external magnetic field works to raise the thruster performance, usually expressed in terms of specific impulse and thrust efficiency. However, this method is not necessarily the best for the thruster system as a whole because of the accompanying increase in its weight and addition of the power supply that is required to produce a given field. The purpose of this study is to overcome these drawbacks through the use of a permanent magnet in place of a solenoidal coil and thereby achieve an MPD thruster with high thruster performance. 5 Refs.