Global confinement in the MST (Madison Symmetric Torus) reversed field pinch

Global confinement measured in the first six months of MST full design operation is summarized. Central electron temperature and enhancement of resistivity over the Z = 1 Spitzer value are similar to other RFP experiments for the same value of I/N. As in several other RFP experiments, energy confinement time and poloidal beta are found to decrease with increasing plasma current, with maximum values of tau(sub E) approximately 1 ms and beta(sub p) approximately 10 percent. Particle transport may be approximated with a diffusion coefficient D approximately 40 sq m/s for a discharge studied with a 1-d particle/neutral code. A more elaborate code, incorporating heat and impurity transport, indicates an increase of Z(sub eff) with I/N. This code also reveals that the toroidal magnetic field decays resistively between discrete dynamo events, at the rate given by the measured global resistivity. Edge suprathermal electrons are observed as on other RFPs, with temperatures comparable to the central electron temperature and carrying a current density at least 15 percent of the total measured with an insertable magnetic coil array. Radial magnetic profiles measured with this array may be matched with a Modified Polynomial Function Model equilibrium for a value of beta(sub p) which is a factor of two larger than measured, but which is required due to the large values of Theta for a given F found in MST discharges (Theta = 1.85 at F = -0.15).