Thermal barrier potential and two-dimensional space-potential measurements with gold neutral-beam probes in GAMMA 10

Gold neutral-beam probes are used for the space-potential measurements in the barrier and in the central cells of the GAMMA 10 tandem mirror. The thermal barrier potential depth is directly observed by simultaneous measurements of the on-axis space potentials at both locations. Two-dimensional space potentials in the barrier region are measured by sweeping the probing beams with different beam energies.