Flux and particle life-time measurements in field-reversed configurations

Abstract

Flux and particle life-times of field-reversed configurations (FRC) have been measured in the TRX-1 field-reversed theta pinch. These measurements have been correlated with detailed numerical transport calculations based on classical and lower-hybrid-drift (LHD) resistivity. The data appear to imply spatially uniform resistivity profiles with a magnitude somewhat lower than that given by the wave energy bound of LHD fluctuations. Using a programmed formation technique it has been possible to form FRCs with large amounts of poloidal flux, and thus large separatrix radii. The particle confinement time has been found to scale approximately linearly with the amount of poloidal flux, and 150 μs particle confinement times have been achieved in 3 X 1015 cm−3 density FRCs with separatrix radii of only 7 cm. The linear scaling with poloidal flux is highly encouraging for scaling to higher-field, larger-size devices.