Development of a three-phase rotating magnetic field system for a compact static plasma source

A rotating magnetic field (RMF) is one of the techniques used to drive an azimuthal electron current in a plasma column. This technique is widely applied in the compact torus (CT) experiments for formation and sustainment of magnetic configurations, since it does not deprive CT of the most important characteristic: a simply-connected structure. When the angular frequency of RMF is high enough, higher than the typical ion cyclotron frequency, electrons are selectively driven and form toroidal current. The RMF applied to an external axial magnetic field forms a closed magnetic field line which provides plasma confinement. Therefore, this method realizes a static plasma source driven solely by an inverter power supply which plays in the roles of formation, sustainment and confinement of the plasma, possibly with a low voltage power supply for external magnetic field. The method may release an ion source from permanent magnets to generate a confined magnetic field. Also, the plasma sustained dominantly by the accelerated electrons substantiates a low-temperature property which is suited for ion sources. To reduce inductive coupling between coils, which becomes tangible especially in small systems, a three-phase RMF system has been proposed and developed in this work.