H-MODES ON COMPASS-D WITH HIGH-POWER ECRH

Recent high-power electron-cyclotron resonance heating (ECRH) H-mode e xperiments on COMPASS-D have used fundamental high-power ECRH to acces s high densities. Within the operating range set by the H-mode density threshold and ECRH accessibility, H-mode power thresholds are signifi cantly higher than expected from ITER scalings, and show a contrary de pendence on density. Energy confinement is somewhat lower than that su ggested by the present ITER scalings, but correction for incomplete RF absorption may be needed. Complex H-mode and ELM behaviour is observe d.