Plasma behavior in a rotating magnetic field

A system was constructed and used to study the behavior of a plasma in a rotating magnetic field in a toroidal system. The plasma with density less than or equal to 1018 m-3, electron temperature approximately 1050K is first formed by rf pre-ionization at low pressure (0.8 m Torr), in the presence of a quasi-steady toroidal magnetic field of 0.4 T. The 1.85 MHz rotating magnetic field is generated by two perpendicular four-turn coils driven in phase quadrature by an amplifier and a variable coupler. Maximum rotating field strength in the presence of a plasma is 1.3 mT. Plasma electron density and temperature are measured with Langmuir probes. Pickup loops are used to determine plasma currents by measuring the magnetic field that they generate