Electron Bernstein Wave Studies on COMPASS‐D and MAST

The present paper reports on electron Bernstein wave (EBW) emission, heating and current drive experiments conducted on COMPASS‐D and MAST. Plasma heating and current drive experiments have been conducted in COMPASS‐D, where EBWs were excited from the high field side of the tokamak at different toroidal launch angles. It has been found experimentally that X‐mode injection perpendicular to the magnetic field provides maximum heating efficiency. Non‐inductive currents of up to 100 kA were found to be driven by the EBW‐mode in the counter direction. This result is consistent with EBW beam‐tracing and quasilinear Fokker‐Planck simulations. EBW emission measurements are a valuable tool for optimisation of heating scenarios. Both X‐mode and O‐mode polarised emission were observed from overdense plasmas at angles perpendicular to the magnetic field and at angles close to the optimum for Bernstein‐extraordinary‐ordinary (B‐X‐O) mode conversion. EBW spectra from high electron cyclotron harmonics are presented and ...