Energy Confinement with ECRH on COMPASS-D.

High power (1.3 MW) Electron Cyclotron Resonance Heating (f=60 GHz) is used in COMPASS-D with plasmas having a single null divertor. Using 2ω_ce ECRH, quasi-stationary discharges with beta_N≈ 2 are produced at q_95≈ 4 for optimised timing of the heating relative to the current ramp up. The duration of the high β phase is not limited by disruptions but by a degradation of the energy confinement, usually caused by MHD relaxation events. These low collisionality plasmas (ν^*< ν^*_ITER) show no H-mode transition and have anomalously good energy confinement (H_L97>2) together with a weak dependence of energy confinement time on electron temperature. Heating at 1ω_ce is used to study the confinement in the ELMy H-mode regime and to generate data for the ITER global confinement database.