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

Xia, Ding; Chen, Xixuan; Xu, Dake; Gang, Fang Jian; ZHANG, Junli; Wang, Nengchao; Yang, Zhoujun; Chen, Zhongyong; Ding, Yonghua; Zheng, Wei; Ma, Shihua; Wang, Zhijiang; Pan, Yuan

doi:10.1088/2058-6272/aca4b5

Cited by 4 publications

(2 citation statements)

References 34 publications

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“…The J-TEXT is a medium-sized tokamak with a major radius R 0 = 1.05 m and a minor radius a = 0.25-0.29 m [34]. The maximum plasma current I p = 220 kA, a typical toroidal magnetic field B t ≤ 2.3 T and the central line averaged electron density n e = (1-7)×10 19 m −3 .…”

Section: Methodsmentioning

confidence: 99%

Suppression of the m/n = 2/1 tearing mode by electron cyclotron resonance heating on J-TEXT

FANG 方,

CHEN 陈,

YAN 严

et al. 2024

Plasma Sci. Technol.

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Stabilization of tearing modes and neoclassical tearing modes is of great importance for the tokamak operation. Electron cyclotron wave (ECW) has been extensively used to stabilize the tearing modes with the virtue of the highly localized power deposition. Complete suppression of the m/n = 2/1 tearing mode (TM) by electron cyclotron resonance heating (ECRH) has been achieved successfully on the J-TEXT tokamak. The effect of ECW deposition location and power amplitude on the 2/1 TM suppression have been investigated. It is found that the suppression is more effective when the ECW power is deposited closer to the rational surface. Partial suppression of the 2/1 TM by ECRH has been observed and the island width is reduced by 65% of the initial island width. The island rotation frequency is increased when the island width is reduced. The experimental results show that the temperature perturbations increase inside the magnetic island produced by the local heating plays a dominant role on tearing modes suppression. As the ECW power increased, the 2/1 island is suppressed to smaller islands width and the flow shear also plays a stabilizing effect on small magnetic islands. With the stabilizing contribution of heating and the flow shear, the 2/1 TM can be completely suppressed.

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Section: Methodsmentioning

confidence: 99%

Suppression of the m/n = 2/1 tearing mode by electron cyclotron resonance heating on J-TEXT

FANG 方,

CHEN 陈,

YAN 严

et al. 2024

Plasma Sci. Technol.

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“…The pulse is constant for all shots shown in this paper. A 105 GHz/500 kW/1 s ECH system was developed in 2019 [9]. Two polarizers on the miter bend can achieve arbitrary polarization, allowing X2-mode ECH assisted start-up to be applied.…”

Section: Methodsmentioning

confidence: 99%

Electron cyclotron heating assisted start-up experiments in J-TEXT

Zhang

Vries²,

Nagasaki³

et al. 2023

EPJ Web Conf.

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Electron cyclotron heating (ECH) breakdown and burn-through assist has been adopted to make the ITER start-up, which uses a low toroidal electric field of about 0.3 V/m, more robust. Related studies have been carried out on many fusion machines such as DIII-D, JT-60U, Tore Supra and FTU. However, the required ECH power to ensure an effective breakdown assist at ITER is not yet clear. Experiment was also performed in J-TEXT to determine the minimum ECH power requirements to assist breakdown and develop a better physics description of the process. The breakdown loop voltage for a successful shot was reduced from 34 to 3.7 V (corresponding to 0.56 V/m) by 300 kW X2-mode ECH power. The critical ECH power to assist the successful formation of a tokamak discharge is about 200kW, and below this value, ionization caused by ECH power is observed, however, the tokamak discharge start-up does not succeed. The effect of different loop voltages and ECH pulse-width on start-up was also studied. As injecting ECH power at a proper time, low ECH power can achieve a similar pre-ionization result as the case with high power. Extremely low breakdown voltage leads to a higher toroidal field later when putting a capacity to continue discharging in J-TEXT. The earlier shutdown of ECH power caused a failed discharge.

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Progress of the electron cyclotron resonance heating system and the related experiments on J-TEXT

Xia,

Chen,

et al. 2024

EPJ Web Conf.

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To augment the capabilities of the J-TEXT tokamak, efforts were undertaken in 2017 to commence the construction of an electron cyclotron resonance heating (ECRH) system. A significant milestone was achieved in 2019 when the successful operation took place using this 105 GHz ECRH system. The system consists of components including the gyrotron from GYCOM, a transmission line spanning approximately 30 meters, and a quasi-optical launcher equipped with an elliptical mirror and movable flat mirror. Another identical system was deployed in 2023 for experimental purposes. Notably, modifications were made to the launcher to support the injection of two beams. Various experiments have been conducted utilizing this system including assisted plasma start-up, control methods for tearing mode, and observations involving toroidal injection of electron cyclotron wave (ECW), etc.

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

Cited by 4 publications

References 34 publications

Suppression of the m/n = 2/1 tearing mode by electron cyclotron resonance heating on J-TEXT

Suppression of the m/n = 2/1 tearing mode by electron cyclotron resonance heating on J-TEXT

Electron cyclotron heating assisted start-up experiments in J-TEXT

Progress of the electron cyclotron resonance heating system and the related experiments on J-TEXT

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