ECRH assisted plasma start-up with toroidally inclined launch; Multi-machine comparison and perspectives for ITER

トロイダル斜めECRH入射によるプラズマ着火アシスト; 複数装置比較とITERへの展望

Stober, J.*; Jackson, G. L.*; Ascasibar, E.*; Bae, Y.-S.*; Bucalossi, J.*; Cappa, A.*; Casper, T.*; Cho, M. H.*; Gribov, Y.*; Granucci, G.*; 花田 和明*; Hobirk, J.*; Hyatt, A. W.*; 井手 俊介; Jeong, J.-H.*; Joung, M.*; Luce, T. C.*; Lunt, T.*; Namkung, W.*; Park, S.-I.*; Politzer, P. A.*; Schweinzer, J.*; Sips, A. C. C.*; ASDEX Upgrade Team*; TJ-II Team*; ITPA "Integrated Operation Scenarios" Group*

Stober, J.*; Jackson, G. L.*; Ascasibar, E.*; Bae, Y.-S.*; Bucalossi, J.*; Cappa, A.*; Casper, T.*; Cho, M. H.*; Gribov, Y.*; Granucci, G.*; Hanada, Kazuaki*; Hobirk, J.*; Hyatt, A. W.*; Ide, Shunsuke; Jeong, J.-H.*; Joung, M.*; Luce, T. C.*; Lunt, T.*; Namkung, W.*; Park, S.-I.*; Politzer, P. A.*; Schweinzer, J.*; Sips, A. C. C.*; ASDEX Upgrade Team*; TJ-II Team*; ITPA "Integrated Operation Scenarios" Group*

ECRH assisted plasma breakdown is foreseen with full and half magnetic field in ITER. As reported earlier, the corresponding O1- and X2-schemes have been successfully used for pre-ionisation and breakdown assist in present day devices. This contribution reports on common experiments studying the effect of toroidal inclination of the ECR beam, which is in ITER. All devices could demonstrate successful breakdown assist also for this case, although in some experiments the necessary power was almost a factor of two higher compared to perpendicular launch. Differences between the devices with regard to the required power and vertical field are discussed and analysed. In contrast to most of these experiments, ITER will build up loop voltage prior to the formation of the field null due to the strong shielding by the vessel. Possible consequences of this difference are discussed.