Recent Progress of 2MW 140GHz ECRH System on HL-2A

A new 140 GHz/2 MW/3 s electron cyclotron resonance heating (ECRH) system composed of two units is now being constructed on HL-2A. As a part of the system, two transmission lines marked No.7 & 8 play the role of carrying microwave power from two gyrotrons to the tokamak port. Based on the oversized circular corrugated waveguide technology, an evacuated transmission system with high power capability and high transmission efficiency is designed. Details are presented for the design of the corrugated waveguide, the layout of the proposed lines and the vacuum pumping system. Then mode conversion losses due to coupling, misalignment, bends and gaps are discussed to serve as a reference for analyzing the transmission efficiency and alignment. Finally, a dual-modes propagation case consisting of the HE11 and LP11 even modes is discussed

Section: Dual-mode Propagationmentioning

confidence: 99%

Design of the Transmission Lines for 140 GHz ECRH System on HL-2A

Xia

Zhou

Rao

2014

“…Among these large-scale scientific facilities, some require gyrotrons at high frequencies [9], such as the International Thermonuclear Experimental Reactor (ITER) [15], the stellarator W7-X [16], DEMO [17], DIII-D [18], EAST [19,20] and HL-2A [9,21].…”

Section: Introductionmentioning

confidence: 99%

Design and experimental results of a 28 GHz, 400 kW gyrotron for electron cyclotron resonance heating

Sun

Huang

et al. 2023

A high power 28 GHz gyrotron has been successfully developed at Institute of Applied Electronics, China Academy of Engineering Physics (IAE-CAEP). This gyrotron was designed for electron cyclotron resonance heating (ECRH) at spherical tokamak XL-50. A diode magnetron injection gun (MIG) was designed to produce the required gyrating electron beam. The gyrotron operates at the TE8,3 mode in a cylindrical open cavity. An internal quasi-optical mode converter was designed to convert the operating mode into a fundamental Gaussian wave beam and separate the spent electron beam from the outgoing microwave power. A tube has been built and successfully tested. The operational frequency of the tube is 28.1 GHz. For beam parameters at an accelerating voltage of 71 kV and beam current of 16 A, the gyrotron has delivered an output power of 400 kW, with a pulse length of 5 s. The output efficiency is about 50% with a single stage depressed collector. The gyrotron has been installed on XL-50 and played an important role in the ECRH experiments.

“…As one of the most promising methods for plasma heating and current profile control, electron cyclotron resonance heating (ECRH) has been widely applied in recent nuclear fusion research (e.g., DIII-D, W7-X, ASDEX-U, EAST, HL-2A) [1][2][3][4][5], and will be developed for future fusion devices. Since 2017, the development of a second-harmonic ECRH system with X-mode injection for Joint-TEXT (J-TEXT) has been initiated.…”

Section: Introductionmentioning

confidence: 99%

Recent progress of the ECRH system and initial experimental results on the J-TEXT tokamak

Xia¹,

Chen²,

Xu³

et al. 2022

In order to broaden the plasma parameters range and provide experimental conditions for physical research of high-performance plasma, the development of electron cyclotron resonance heating (ECRH) system for the J-TEXT tokamak has been initiated since 2017. At first stage, the ECRH system has realized successful operation with one 105 GHz/500 kW/1 s gyrotron in 2019. More than 400 kW electron cyclotron (EC) wave power has been injected into the plasma successfully, raising the core electron temperature to 1.5 keV. In 2022, another 105 GHz/500 kW/1 s gyrotron has finished the commissioning tests which signify that the ECRH system could generate EC wave power of 1 MW in total. Under the support of the ECRH system, various physical experiments have been carried out on J-TEXT. The electron thermal transport in ECRH plasmas has been investigated. When ECRH is turned on, the electron thermal diffusivity significantly increases. The runaway current is elevated when a disruption occurs during ECRH heating. When the injected EC wave power is 400 kW, the conversion efficiency of runaway current increases from 35% to 75%. The fast electron behavior is observed in electron cyclotron current drive (ECCD) plasma by fast electron bremsstrahlung diagnostic (FEB). The increase in the FEB intensity implies that ECCD could generate fast electrons. A successful start-up with a 200 kW ECW is achieved. With the upgrade of the ECRH system, the J-TEXT operational range could be expanded and more relevant research could be further conducted.