Simulation of helicon wave current drive on the Experimental Advanced Superconducting Tokamak under high poloidal beta scenarios

The high poloidal beta (beta p) scenario serves as a promising operational mode for tokamak fusion reactors. In this paper, the helicon wave current drive under high beta p scenarios on the EAST device is studied numerically. Theoretical analysis based on the fast wave dispersion relation indicates that a higher wave frequency enhances wave power absorption in the device. GENRAY/CQL3D simulations indicate that an effective on-axis plasma current drive can generally be achieved. Scans of plasma parameters reveal that lower plasma density and higher plasma temperature contribute to higher current drive efficiency. Moreover, a scheme of combined current drive using lower hybrid waves and helicon waves in the device is analyzed, resulting in significant complementarity in the current drive profile and a positive synergistic effect on the net current drive. This work is expected to provide a new perspective for the next stage of EAST operations.