On Rotation in Plasmas with Electron Heating by ICRH

Rotation of L-mode plasmas in the JET tokamak heated by waves in the Ion Cyclotron Range of Frequencies (ICRF) damped on electrons is reported. The plasma is found to rotate in the counter current direction in the core with high shear. The rotation is stronger in magnitude than observed for scenarios with dominating ion cyclotron absorption. Two scenarios are considered: the inverted mode conversion scenarios and heating at the second harmonic 3He cyclotron resonance in H-plasmas. In the latter case electron absorption of the fast magnetosonic wave by Transit Time Magnetic Pumping and Electron Landau Damping (TTMP/ELD) is the dominating absorption mechanism. Inverted mode conversion is done in (3He)-H plasmas where the mode converted waves are essentially absorbed by electron Landau damping. Similar rotation profiles are seen when heating at the second harmonic cyclotron frequency of 3He and with mode conversion at high concentrations of 3He. The magnitude of the counter rotation is found to decrease with increasing plasma current. The correlation of the rotation with the electron temperature is better than with coupled power indicating that for these types of discharges the dominating mechanism for the rotation is related to indirect effects of electron heat transport rather than to direct effects of ICRF-heating.
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