Formation of field-reversed configuration using an in-vessel odd-parity rotating magnetic field antenna in a linear device

A Field-Reversed Configuration (FRC) is formed by an in-vessel odd-parity rotating magnetic field (RMF) antenna in a tandem mirror device, Keda mirror with axisymmetricity. The 40-cm diameter antenna is fed independently by four IGBT-based power units with an output current of 1500 A each at 84 kHz, and their phases are adjustable to launch odd or even parity RMFs. A medium-sized washer gun is utilized to generate a highly ionized seed hydrogen plasma. Driven by RMF, the resultant FRC is formed with a separatrix radius of ∼17 cm, external field of ∼50 G, and trapped poloidal flux of ∼0.15 mWb. The formation process of FRCs is evidenced by the measurement of an array of internal two-dimensional probes; a comparison with the rigid rotor model is presented in this paper. In addition, substantial toroidal electron current is found to be driven, despite the partial RMF penetration. Moreover, the dependence of the driven current on the antenna current is reported and is found to be consistent with the RMF current driving model.