Gonfinement Transitions in the H - l Heliac

Experiments at low magnetic field (< 0.2 T) in the H-1 heliac show transitions in confinement at low temperature and low heating power-50 kW. These transitions exhibit many of the features seen in L-H transitions in large tokamaks and stellarators: steepening of the density gradient, increases in the radial electric field, suppression of turbulence, and increased ion energies. Future experiments in H-1 will attempt to extrapolate these phenomena to higher magnetic fields 0.5 < I < 1 T and heating power P > 0.5 MW and study confiinement in finite-pressure helical-axis plasmas.