会議発表用資料 Nonlinear contribution of neutral beam injection in TCV EC-heated advanced tokamak scenarios

Vallar, M.  ,  Agostini, M.  ,  Bolzonella, T.  ,  Coda, S.  ,  Garcia, J.  ,  Geiger, B.  ,  Goodman, T.  ,  Gorelenkova, M.  ,  Karpushov, A.N.  ,  T., Kurki-Suonio  ,  Piron, C.  ,  Pigatto, L.  ,  Sauter, O.  ,  Vianello, N.  ,  Vincenzi, P.  ,  吉田, 麻衣子

2018-07-02
内容記述
TCV is a tokamak device capable of many different plasma shapes, equipped with a flexible Electron Cyclotron (EC) system and since 2016 with a heating Neutral Beam (NB) injector. The EC system incorporates two subsystems: X2 (second harmonic) used for electron heating up to cutoff density with efficient current drive; X3 extends the density range for EC heating up to higher density (cutoff limit) suitable for H-mode confinement regime. The X2+X3 EC power available for the experiments studied here was 2.5 MW. The maximal NB power was up to 1.05 MW, using the tangentially injected beam with full energy of 25 keV at maximal power. Compared to the past, when fully non-inductive plasmas sustained using EC waves only were obtained, the operating space of advanced tokamak scenarios in TCV has been now extended towards higher plasma current and density with NB+EC heating scheme. These scenarios, characterized by high βN, high non-inductive current fraction and a relevant energetic particle (EP) population fraction (~10% ne) are envisaged as potential candidates for the regular future tokamak reactor operation due to their high fusion power generation and low inductive current requirements and outline the basis for future JT60-SA high-β experimental program. An internal transport barrier can be generated by reversing the q-profile using EC current-drive (ECCD). A strong contribution of bulk ions and EP to plasma pressure and total energy in performed plasma discharges is illustrated in Figure 1: the plasma β is clearly decorrelated from electron thermal energy and this is caused by an interplay between neutral beam injection (NBI) and ECH.
The 45th European Physical Society Conference on Plasma Physics

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