Parametric study of helicon wave current drive in CFETR

This paper evaluates the feasibility of helicon current drive (HCD) in a hybrid scenario for the China Fusion Engineering Test Reactor (CFETR). Utilizing the GENRAY/CQL3D package, a large number of simulations (over 5000) were conducted, with parametric scans in the antenna’s poloidal position, launched parallel refractive index (n|| ), and wave frequency. The analysis reveals that helicon has excellent accessibility under reactor-level conditions, and smaller n|| and higher wave frequency result in enhanced wave absorption. The simulations demonstrate an optimal launched n|| of approximately 1.6 for the CFETR hybrid scenario, with helicon achieving a maximum drive efficiency of 2.8 × 10¹⁹ A·W⁻¹·m⁻². The best launch position is found to be within a poloidal angle range of 25 degrees to 65 degrees. Additionally, it is preferable to have a narrow n|| spectrum for wave absorption when operating below the threshold value of Δn|| (∼0.6), beyond which the effect of Δn|| on wave absorption is negligible. This study provides valuable insights into the potential application of HCD in CFETR.