Tilt stability and compression heating studies of field-reversed configurations

The first comprehensive observations of internal tilt instabilities in field-reversed configurations (FRCs) are reported. Comparisons with 3-D simulations establish that data from an array of external magnetic probes are signatures of these destructive plasma instabilities. This work is a major step towards reconciling theory and experiments, and it suggests that grossly stable FRCs are restricted to very kinetic and elongated plasmas. Self-consistent 3-D numerical simulations demonstrate tilt stabilization by the addition of a beam ion component. High-power compression heating experiments with stable equilibrium FRCs are also reported. Plasmas formed in a tapered theta pinch have been translated along a guide magnetic field into a new single-turn compression coil where the external field is increased up to 7 times the initial value in 55 μs. Substantial heating is observed accompanied by a decrease in confinement times. (author). 17 refs, 4 figs, 1 tab