Reconstruction Progress of the COMPASS-D ECRH System on J-TEXT

Abstract

To make the J-TEXT tokamak more flexible for physics experiments, an electron cyclotron resonance heating (ECRH) system is being developed. The main parts of the J-TEXT ECRH system are donated by the Culham Science Center from the former COMPASS-D, including six 60 GHz/200 kW/5 s (0.5 s) gyrotrons, six magnets, and auxiliary power supplies for the gyrotrons, transmission parts, and so on. For the ECRH system, the output mode of the gyrotron from the former Varian Associates, Inc. is TE $_{{\mathrm {02}}}$ mode and converted to TE $_{{\mathrm {01}}}$ mode for low loss transmission. The TE $_{{\mathrm {01}}}$ –TE $_{{\mathrm {11}}}$ –HE $_{{\mathrm {11}}}$ mode converter is used at the end of the transmission lines for efficient coupling. Then, the high-power wave is injected to the desired area of the plasma by a rotatable quasi-optical launcher. A 100 kV/60 A power supply based on a pulse step modulation technology has been developed to feed all the gyrotrons. The control system based on the compact reconfigurable I/O—9068 platform of National Instruments for monitoring, timing, and protection is being designed. Other units, such as the cooling loops, the launcher, and a spared auxiliary power supply, are on the way. We hope that four subsystems can be finally used on J-TEXT.