Development and initial operation of the ICRF system on the J-TEXT tokamak

A two-chain ion cyclotron range of frequency (ICRF) system has been developed and commissioned on the J-TEXT tokamak, with the primary objective of establishing a controllable experimental platform for systematic studies of antenna–plasma coupling under reproducible edge plasma conditions. Although ICRF systems are commonly used for plasma heating, the present work focuses on the first-stage objective of system development, commissioning and coupling-oriented operation, while future work will extend to ICRF heating experiments, including minority-heating scenarios. The system operates in the frequency range of 20–35 MHz and consists of two RF generator chains, transmission lines with matching and decoupling components, a two-strap antenna, and associated diagnostics. Each RF generator has a rated output power of up to 200 kW with a pulse duration of 1 s. Initial operation in hydrogen plasmas demonstrates that stable RF operation and effective antenna–plasma coupling can be achieved under typical discharge conditions, while antenna phasing and coupling behaviour can be monitored during RF power injection. These results provide a technical and experimental basis for subsequent systematic coupling studies and future ICRF heating experiments on J-TEXT.