An experimental and computational study of compact torus formation, decay and heating in the Berkeley Compact Torus Experiment

A spheromak type compact torus (CT) plasma is investigated by studies of th e gun type plasma formation mechanism and from the characteristics of the m agnetic decay following the establishment uf a CT equilibrium in the flux c onserver. Radiofrequency heating in the lower hybrid range (432 MHz) is use d tu study the electron heat confinement using a 20 MW, 100 mu s power puls e. While electron temperatures up to 200 eV have been measured with RF heat ing, the impact on magnetic decay from the RF heating is relatively weak. A simple model based upon parallel electron heat transport along stochastic magnetic field lines gives a scaling lan for magnetic decay which fits the experimental data. Results: of two dimensional MHD code calculations are gi ven which match many details of the experimentally observed formation physi cs.