Ion heating and confinement in the HBTX1C reversed field pinch

A distinguishing feature of RFPs is that both the plasma resistance and ion heating are much higher than expected from classical, or collisional, considerations. Ion power balance models have been proposed elsewhere which link these effects through magnetic helicity balance, including helicity losses at the edge. These models incorporate the MHD dynamo electric field, generated by the fluctuations in the fluid velocity, v, and the magnetic field, B. Here we have conducted a series of experiments and measurements which focus separately on the various aspects of the ion dynamics in HBTX1C. These encompass (i) altering the ohmic input power by impurity injection; (ii) measuring the particle confinement time by the laser ablation method; (iii) measurements of the ion power loss and (iv) measuring the temperature and rotational velocities, of impurities. (author) 13 refs., 3 figs