Formation of neoclassical internal transport barriers under various operational regimes on compact helical system

Optimization has been carried out on the operational regime where neoclassical internal transport barriers (N-ITBs) are formed. The condition of the forming N-ITB is sensitive to the location of the electron cyclotron heating resonance zone. A high electron temperature is obtained for the central heating (−2 cm < Rresonance < 2 cm). The variation of the magnetic axis location affects the formation of the N-ITB. The electron and ion temperatures at the magnetic axis location (Rax) of 94.9 cm are higher than those at 92.1 and 97.4 cm. This result indicates that the neoclassical flux and the created radial electric field are influenced by the magnetic field structure.