Edge measurements during Alfven wave heating and current drive on the Phaedrus-T tokamak
Summary form only given, as follows. The properties of tokamak boundary plasmas play an important role in the success of using waves in the ion cyclotron range of frequency for heating and current drive. Edge measurements have been conducted on the Phaedrus-T tokamak under a variety of operating conditions to study the relevant processes in coupling Alfven wave power to plasma and the effects of Alfven waves on the plasma boundary. With the adjustment of gas puffing, the line density during rf can be successfully controlled and kept at the same constant level as ohmic on the Phaedrus-T tokamak. The edge density is then found to have no significant change with the application of Alfven waves. Edge electron temperature, however, is found to increase with increasing rf power and the rise time is much shorter than the energy confinement time, which indicates direct power deposition in the boundary of the plasma. Some data suggest less edge heating corresponds to better rf power coupling to the bulk plasma. Edge electrostatic fluctuation measurements show increases in the fluctuation induced particle flux and heat flux during rf, indicating a degradation of particle and energy confinement time by the Alfven waves. The effects of rf phasing will also be discussed.