ECRH CURRENT DRIVE STUDIES IN THE CLEO TOKAMAK
Non-inductive current drive using second harmonic ECRH at both 28 GHz and 60 GHz has been studied in the CLEO tokamak. At 60 GHz RF driven currents of up to 5 kA have been observed at =n-e = 4 times 10"18" m"-3" for 185 kW of injected power indicating an efficiency of eta equiv =n-e I-"rf"R-o/P-"rf" = 0.001 (10"20" m"-3" AmW"-1"). The RF driven current scaled linearly with total plasma current in the range 5--15 kA and was maximised when the cyclotron resonance was located near to the centre of the plasma. Sawtooth activity was normally strongly affected and transient sawtooth stabilisation was often observed. Detailed theoretical studies are able to reproduce both the high absorption efficiencies and the scaling of RF driven current with resonance position seen in the 60 GHz experiments. However the magnitude of the observed current is a factor of sim 3 below that theoretically predicted. At 28 GHz no evidence of RF driven currents could be detected. Possible reasons for this are discussed.
Bibliographic Reference: REPORT CLM-P830, 1987, AVAILABILITY: UKAEA, ABINGDON, UK
Record Number: 1989126082300 / Last updated on: 1989-05-01
Available languages: en