Approaching to the ideal condition of plasma confinement by applying external resonant fields in IR-T1 tokamak

For understanding the effect of resonant helical magnetic field (RHF) and bias on the edge plasma turbulent transport, the radial and poloidal electric field (E_r, E_P ), poloidal and toroidal magnetic field (B_P, B_r ) were detected by the Langmuir probe, magnetic probe and diamagnetic loop. The poloidal, toroidal and radial velocity (V_P, V_r, V_t ) can be determined from the electric and magnetic field. In the present work, we have investigated the effect of the magnitude of bias (V _bias = 200v, V _bias = 320v) on E_r, E_P, B_P, B_t, V_P, V_r, V_t . Moreover, we applied RHF with L = 2, L = 3 and L = 2 and 3 and investigate the effect of the helical windings radius on above parameters. Also, the experiment was repeated by applying the positive biasing potentials and RHF's simultaneously. The results show that by applying bias to the plasma at t = 15 msec at r/a = 0.9, E_r , B_P and B_t increase while E_P decreases. The best modification occurs at V _bias = 200v. By applying RHF to the plasma, both the electric and magnetic field vary. E_r reaches the highest in the presence of RHF with L = 3. The same results are obtained for B_P, B_t, V_P and V_t . While the inverse results are obtained for E_P and V_r . Finally, RHF and bias are applied simultaneously to the plasma. With applied bias with V _bias = 200v and RHF with L = 2 and 3, we reach to the ideal circumstance. The same results obtain in the situation with V _bias = 320v and RHF with L = 2 and 3.