Fast Electron Generation and Transport in a Turbulent, Magnetized Plasma.

The nature of fast electron generation and transport in the Madison Symmetric Torus (MST) reversed field pinch (RFP) is investigated using two electron energy analyer (EEA) probes and a thermocouple calorimeter. The parallel velocity distribution of the fast electron population is well fit by a drifted Maxwellian distribution with temperature of about 100 eV and drift velocity of about 2times10 ^6 m/s. Cross-calibration of the EEA with the calorimeter provides a measurement of the fast electron perpendicular temperature of 30 eV, much lower than the parallel temperature, and is evidence that the kinetic dynamo mechanism (KDT) is not operative in MST. The fast electron current is found to match to the parallel current at the edge, and the fast electron density is about 4 times10^{11} cm^ {-3} independent of the ratio of the applied toroidal electric field to the critical electric field for runaways (E_phi/E_{crit }). Time resolved measurements of the fast electron distribution indicate that it is not directly correlated with E_phi/E_{crit } in a single discharge. First time measurements of magnetic fluctuation induced particle transport are reported. By correlating electron current fluctuations with radial magnetic fluctuations the transported flux of electrons is found to be negligible outside r/a ~ 0.9, but rises the level of the expected total particle losses inside r/a ~ 0.85. A comparison of the measured diffusion coefficient is made with the quasilinear stochastic diffusion coefficient. The measured diffusion is found to be 500 m^2 /s, smaller than the quasilinear value of 2000 m ^2/s. Evidence exists that the reduction of the transport is due to the presence of a radial ambipolar electric field of magnitude 500 V/m, that acts to equilibrate the ion and electron transport rates. The convective energy transport associated with the measured particle transport is large enough to account for the observed magnetic fluctuation induced energy transport in MST.