Design and analysis of radio frequency window for the China Fusion Engineering Test Reactor ion cyclotron range of frequency heating system

Abstract

The Ion Cyclotron Range of Frequency (ICRF) heating system of the China Fusion Engineering Test Reactor (CFETR) is intended to provide plasma heating with a minimum power output of 20 MW, which demands the Radio Frequency (RF) window to possess a higher performance requirement. This paper presents the design of an RF window for the CFETR ICRF heating system and focuses primarily on the design and confirmation of its electromagnetic performance. The RF window can be effectively matched in the operating frequency range and has an S11 of under −59 dB. The geometry of the cone type ceramics was optimized to reduce the surface tangential electric field distribution. An analysis of the electric field distribution of the RF window at 50 kV indicates that the pressure side was below 2.3 kV/mm and the vacuum side was below 1.3 kV/mm. Furthermore, a transmission line test bench with an open-terminated setup was constructed to conduct withstand voltage tests on the mockup, and the results showed that the mockup could withstand 62 kV for 2 s and 47 kV for 120 s.