Simulations of ICRF mode conversion heating in the CN-H1 stellarator

Abstract A full-wave simulation study on minority ion heating has been conducted on the CN-H1; however, the possible mode conversion processes involved have not been thoroughly investigated. This work extends previous minority heating studies by investigating Ion Cyclotron Range of Frequencies (ICRF) mode conversion heating mechanisms in the helical device CN-H1, via analysis of full-wave simulation results, to gain deeper insights into the mode conversion processes. In the simulation study of Ion Cyclotron Resonance Heating ( ICRH ) for CN-H1, mode conversion was observed, with distinct ion Bernstein waves (IBW) propagating toward the high-field side and ion cyclotron waves (ICW) propagating toward the low-field side identified, along with electron absorption. The results demonstrate that an effective scheme for enhancing electron power deposition comprises: a low-field-side mode conversion layer near the plasma core, a hydrogen concentration between 4% and 10%, a wave frequency of 6.6 MHz, a toroidal mode number of n = 7, and sufficiently high electron temperature and density. This work provides a theoretical foundation for optimizing future ICRF experiments on CN-H1.