RECENT RESULTS ON ION-CYCLOTRON AND COMBINED HEATING OF TEXTOR

The recent experimental activity in the field of auxiliary heating and related topics on TEXTOR is reviewed. TEXTOR is equipped with up to 4 MW of ion cyclotron heating power and 3.4 MW of neutral beam injectio n. The combination of the radiating boundary concept with high auxilia ry power has extended the improved confinement domain to the large den sity regime and demonstrated the viability of the radiating boundary c oncept for long pulse high power operation. Improved confinement was a lso achieved in third harmonic heating, characterised by predominant c oupling of the RF to the beam ions. Operation of an unshielded antenna with insulated limiters proved that RF sheaths are taking place on th e side limiters and are suppressed by insulation. Control of the heliu m flux by the RF was successfully demonstrated using the interaction o f the RF with fast He-3 ions injected by neutral beam. Preliminary tes ts with a high Z limiter indicate compatibility, and even a positive e ffect, of the RF. Experience gained in operating unshielded antennas i s also commented on.