TURBULENT TRANSPORT IN THE MADISON SYMMETRICAL TORUS REVERSED-FIELD PINCH

Measurements of edge turbulence and the associated transport are ongoing in the Madison Symmetric Torus (MST) reversed-field pinch [Fusion Technol. 19, 131 (1991)] using magnetic and electrostatic probes. Magnetic fluctuations are dominated by m = 1 and n approximately 2R/a, tearing modes. Particle losses induced by magnetic field fluctuations have been found to be ambipolar ( [J(parallel-to) B(r)]/B0 = 0). Electrostatic fluctuations are broadband and turbulent, with mode widths DELTA-m approximately 3-7 and DELTA-n approximately 70-150. Particle, parallel current, and energy transport arising from coherent motion with the fluctuating E X B drift have been measured. Particle transport via this channel is comparable to the total particle loss from MST. Energy transport (from [PE(phi)]/B0) due to electrostatic fluctuations is relatively small, and parallel current transport (from [J(parallel-to) E(phi)]/B0) may be small as well.