Magnetic probe measurements of compact toroid formation experiments

Magnetic loop probes with areas ranging from 0.2 to 0.9 cm2 were used to observe azimuthal, radial, and axial magnetic fields versus time at 28 locations in Compact Toroid formation discharges. The probes were enclosed in 6 mm outer diameter, 4 mm inner diameter glass tubes which were inserted through the 90 cm diameter inner (electrically hot) electrode. Probe signals were sent to an array of Tektronix 7903 oscilloscopes via fiber optic links. Typical field values ranged from 0.1 to 2 Tesla. Typical discharge currents were -3 microsecond rise time. Probe calibrations, experimental field distribution histories, and comparison with 2D-MHD predictions are discussed. Such comparisons show good agreement