Heating, confinement and fluctuations in the CLEO stellarator

The confinement of an Ohmically heated plasma has been investigated in the CLEO stellarator. The electron energy replacement time is found to decrease as the drift parameter, characterized by the ratio of electron drift velocity to electron thermal velocity, is increased. Density fluctuations have been seen but do not appear to explain the observed loss as being due to a drift instability. A beam of neutrals has been injected into a plasma produced by Ohmic heating: ion heating has been observed. The results have been compared with theoretical models. It is shown that increased power input will be necessary to sustain a currentless plasma of the same parameters as those produced by Ohmic heating. (author)