Status of the ITER Ion Cyclotron H&CD system

The ongoing design of the ITER Ion Cyclotron Heating and Current Drive system (20 MW, 40–55 MHz) is rendered challenging by the wide spectrum of requirements and interface constraints to which it is subject, several of which are conflicting and/or still in a high state of flux. These requirements include operation over a broad range of plasma scenarios and magnetic fields (which prompts usage of wide-band phased antenna arrays), high radio-frequency (RF) power density at the first wall (and associated operation close to voltage and current limits), resilience to ELM-induced load variations, intense thermal and mechanical loads, long pulse operation, high system availability, efficient nuclear shielding, high density of antenna services, remote-handling ability, tight installation tolerances, and nuclear safety function as tritium confinement barrier. R&D activities are ongoing or in preparation to validate critical antenna components (plasma-facing Faraday screen, RF sliding contacts, RF vacuum windows), as well as to qualify the RF power sources and the transmission and matching components. Intensive numerical modeling and experimental studies on antenna mock-ups have been conducted to validate and optimize the RF design. The paper highlights progress and outstanding issues for the various system components.

► We summarize the progress and outstanding issues in the development of the ITER Ion Cyclotron Heating and Current Drive (IC H&CD) system.
► The system is designed to robustly couple 20 MW in quasi-CW operation for a broad range of plasma scenarios, and is upgradeable to up to 40 MW.
► The design is rendered challenging by the wide spectrum of requirements and interface constraints to which it is subject.
► R&D is ongoing to validate key antenna components, and to qualify the radio-frequency (RF) sources and the transmission and matching components.
► Intensive numerical modeling and experimental studies on antenna mock-ups have been conducted to validate and optimize the RF design.