Modeling of the control of the driven current profile in ICRF MCCD on EAST plasma

Abstract

Control of the current profile is a crucial issue for improved confinement and the inhibition of instability in advanced tokamak operation. Using typical discharge data for the Experimental Advanced Superconducting Tokamak, numerical simulations of driven-current profile control in mode conversion current drive (MCCD) in the ion cyclotron range of frequencies were performed employing a full-wave method and Ehst–Karney efficiency formula. Results indicate that the driven current profile in MCCD can be effectively modified by shifting the mode conversion layer. The peak of the driven current can be located at an aimed position in the normalized minor radius range (−0.60≤r/a≤0) by changing the radiofrequency and the minority-ion concentration. The efficiency of the off-axis MCCD can reach 233 kA/MW through optimization, and the mode converted ion cyclotron wave plays an important role in such scenarios. The effects of electron temperature and plasma density on the driven current profile are also investigated.