Internal Magnetic Field Measurements in the TCSU RMF Current Drive Experiment

Abstract

Detailed magnetic measurements of Field-reversed configurations (FRC) from the Translation Confinement Sustainment Upgrade (TCSU) experiment are presented. A two-axis probe inserted transversely at the axial midplane provides 24 independent measurements of B z (r) and B x (r). Two single-axis 29 channel probes provide axial profiles at the plasma edge. The B x (r) field profiles, oriented to measure Bθ from the rotating magnetic field (RMF), provide details about RMF penetration into the FRC. B z (r) profiles, when combined with the high beta nature of the FRC, interferometric density measurements, and assuming uniform temperature, yield radial density and pressure profiles. Time evolution of these profiles gives insight into plasma dynamics and the n = 1 (wobble) and n = 2 instabilities. Data from 123 and 172 kHz RMF frequencies is presented.