Strong radial electric field shear and reduced fluctuations in a reversed-field pinch

摘要

A strongly sheared radial electric field is observed in enhanced confinement discharges in the MST reversed-field pinch. The strong shear develops in a narrow region in the plasma edge. Electrostatic fluctuations are reduced over the entire plasma edge with an extra reduction in the shear region. Magnetic fluctuations, resonant in the plasma core but global in extent, are also reduced. The reduction of fluctuations in the shear region is presumably due to the strong shear, but the causes of the reductions outside this region have not been established.