This paper investigates the characteristics of helicon wave current drive (HCD) on the high-field-side and low-field-side of a spherical tokamak through numerical simulations. The simulations are based on the equilibrium configuration of the EXL-50U device, analyzing the current drive efficiency under different frequency, temperature, and density conditions. The results show that a helicon wave at 350 MHz can drive a significant current under the given temperature and density distribution. Under low-density conditions, the low-field-side HCD outperforms the high-field-side. However, as the ele...
