Momentum transport and flow damping in the reversed-field pinch plasma

A biased electrode is used in the Madison Symmetric Torus (MST) reversed-field pinch [Fusion Technol. 19, 131 (1991)] to manipulate plasma flow in order to study flow damping and momentum transport. Finite radial conductivity allows a radial current, which provides the toroidal torque that spins up the plasma. The applied torque is balanced by a viscous force that opposes toroidal flow acceleration. From the plasma flow damping the viscosity is inferred to be anomalous. The radial transport of toroidal momentum is comparable to that of particles and energy, and is consistent with transport by stochastic magnetic field lines.