Turbulent transport in the Madison Symmetric 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 ∼2R/a, tearing modes. Particle losses induced by magnetic field fluctuations have been found to be ambipolar (left-angle Jparallel Br right-angle/B0=0). Electrostatic fluctuations are broadband and turbulent, with mode widths Δm∼3--7 and Δn∼70--150. Particle, parallel current, and energy transport arising from coherent motion with the fluctuating ExB drift have been measured. Particle transport via this channel is comparable to the total particle loss from MST. Energy transport (from left-angle PEφ right-angle/B0) due to electrostatic fluctuations is relatively small, and parallel current transport (from left-angle Jparallel Eφ right-angle/B0) may be small as well