No abstract

Power measurement is necessary for an electron cyclotron resonance heating (ECRH) system. The directional coupler method has been put forward to monitor high-power microwave from gyrotrons in real time. A multi-hole directional coupler has been designed and manufactured for the 105 GHz/500 kW ECRH system on J-TEXT tokamak. During the design process, we established the relationships between hole parameters and coupling characteristics based on the multi-hole coupling method and small-hole coupling theory. High-power tests have been carried out. The results indicated the reasonability of the theoretical design and practicality of the fabricated directional coupler. Sources of test errors have been discussed in detail, and the influences of spurious modes on the directional couplers have been emphatically analyzed.

Power measurement is necessary for an electron cyclotron resonance heating (ECRH) system. The dummy load is one of the significant equipment for the millimeter wave power measurement. In this paper, The dummy load is analyzed based on the quasi-optical method and the ray tracing method. The reflectivity and thermal deposition of the dummy load has been considered to ensure the safety of the whole system. High-power tests have been carried out at a 105 GHz/500 kW ECRH system. The results of the tests indicate that the dummy load is stable and valid.

No abstract

A 105 GHz/500 kW/1 s electron cyclotron resonance heating (ECRH) system has been developed on J-TEXT tokamak since 2017. The core component of the ECRH system is a gyrotron manufactured by Gyrotron Complexes Ltd. (GYCOM Ltd.), which generates microwaves of a certain frequency and power. To guarantee safe and stable operation, it is necessary to design a specialized control system. The control system is expected to perform time sequence trigger, protection, signal monitoring, communication, and data acquisition. The hardware is built with real-time processors and data acquisition modules from National Instruments. The control program is realized by LabVIEW. Test results indicate that the control system can commit stable and safe operation of the gyrotron, which guarantees the integrated commissioning tests of the whole ECRH system and ECRH related physics experiments. Under the operation of this control system, the gyrotron can generate microwaves as expected, and the ECRH system is well protected when a fault takes place.