Suppression of runaway current generation by supersonic molecular beam injection during disruptions on J-TEXT

Huang, Dan; Chen, Z Y; Tong, R. H.; Yan, Wei; Wang, S Y; Wei, Yunong; K, T; Dai, A.J.; Wang, X L; Jiang, Zhonghe; Yang, Zhoujun; Zhuang, G.; Pan, Yuan; Team, J-Text

doi:10.1088/1361-6587/aa717c

Cited by 11 publications

(10 citation statements)

References 49 publications

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“…The Phase-II operation preparation of ADITYA-U included calibration of magnetic diagnostics followed by commissioning of major diagnostics and installation of a baking system [15]. The Phase-II plasma operation of ADITYA-U was focused on carrying out experiments including primary and secondary RE control [16,17], injection of a supersonic molecular beam during current flat-top and disruption [18,19], confinement improvement with neon injection [20] with the execution of real-time plasma position feedback control [21]. The results of these experiments are very promising and may play a vital role in the operation of large-size fusion machines, including ITER.…”

Section: Introductionmentioning

confidence: 99%

Overview of operation and experiments in the ADITYA-U tokamak

et al. 2019

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First indigenously built tokamak ADITYA, operated over 2 decades with circular poloidal limiter has been upgraded to a tokamak named ADITYA Upgrade for the purpose having shape plasma operation with open divertor geometry. Experiment research in ADITYA-U has made significant progress, since last FEC 2016. After installation of PFC and standard tokamak diagnostics, the Phase-I plasma operations were conducted from December 2016 with graphite toroidal belt limiter. Purely Ohmic discharges in circular plasmas supported by Filament pre-ionization was obtained. The plasma parameters, Ip ~ 80-95 kA, duration ~ 80-180 ms with toroidal field (max.) ~ 1T and chord-averaged electron density ~ 2.5 x 10^19 m^-3 has been achieved. Being a medium sized tokamak, runaway electron (RE) generation, transport and mitigation experiments have always been one of the prime focus of ADITYA-U. MHD activities and density enhancement with H2 gas puffing studied. The Phase-I operation was completed in March 2017. The Phase-II operation preparation in ADITYA-U includes calibration of magnetic diagnostics followed by commissioning of major diagnostics and installation of baking system. After repeated cycles of baking the vacuum vessel up to ~ 130°C, the Phase-II operations resumed from February 2018 and are continuing to achieve plasma parameters close to the design parameters of circular limiter plasmas using real time plasma position control. Hydrogen gas breakdown was observed in more than ~2000 discharge including Phase-I and Phase-II operation without a single failure. Several experiments, including the primary RE control with lower E/P operation and secondary RE control with fuelling of Supersonic Molecular Beam Injection as well as sonic H2 gas puffing during current flat-top and Neon gas puffing for better plasma confinement are undergoing. The dismantling of ADITYA and reassembling of ADITYA-U along with experimental results of Phase-I and Phase-II operations from ADITYA-U will be discussed.

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Section: Introductionmentioning

confidence: 99%

Overview of operation and experiments in the ADITYA-U tokamak

et al. 2019

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“…The SMBI excites magnetic islands, as long as the injected hydrogen quantity is above a certain threshold in J-TEXT [48]. Moreover, the RE loss increased rapidly if large TMs were excited [43]. By applying SMBI to induce TMs with sufficient amplitude, the generation of REs can be completely suppressed during the MGI triggered disruptions, as shown by discharges #1041920 and #1041921 in figure 10.…”

Section: Suppression Of Res By Rmp and Smbimentioning

confidence: 98%

“…Reprinted from [10], with the permission of AIP Publishing. magnetic perturbations [40][41][42][43] in the disruptions triggered by the massive gas injection (MGI). The first result on the disruption mitigation by using the SPI system is also presented [10].…”

Section: Progress On the Disruption Mitigationmentioning

confidence: 99%

“…The RE confinement can be influenced by the magnetic topology change from the nested flux surfaces, hence the RE generation can be significantly impacted. In J-TEXT, the formation of magnetic island or even stochastic layer can be actively driven by applying either supersonic molecular beam injection (SMBI) [43] or RMP fields [40][41][42] before the MGI triggered disruption occurs, and the RE can be suppressed.…”

Section: Suppression Of Res By Rmp and Smbimentioning

confidence: 99%

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Overview of the recent experimental research on the J-TEXT tokamak

et al. 2019

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Recent J-TEXT research has highlighted the significance of the role that non-axisymmetric magnetic perturbations, so called three-dimensional (3D) magnetic perturbation (MP) fields, play in a fundamentally 2D concept, i.e. tokamaks. This paper presents the J-TEXT results achieved over the last two years, especially on the impacts of 3D MP fields on magnetohydrodynamic instabilities, plasma disruptions and plasma turbulence transport. On J-TEXT, the resonant MP (RMP) system, capable of providing either a static or a high frequency (up to 8 kHz) rotating RMP field, has been upgraded by adding a new set of 12 in-vessel saddle coils. The shattered pellet injection system was built in J-TEXT in the spring of 2018. The new capabilities advance J-TEXT to be at the forefront of international magnetic fusion facilities, allowing flexible study of 3D effects and disruption mitigation in a tokamak. The fast rotating RMP field has been successfully applied for avoidance of mode locking and the prevention of plasma disruption. A new control strategy, which applies pulsed RMP to the tearing mode only during the accelerating phase region, was proved by nonlinear numerical modelling to be efficient in accelerating mode rotation and even completely suppresses the mode. Remarkably, the rotating tearing mode was completely suppressed by the electrode biasing. The impacts of 3D magnetic topology on the turbulence has been investigated on J-TEXT. It is found that the fluctuations of electron density, electron temperature and plasma potential can be significantly modulated by the island structure, and a larger fluctuation level appears at the X-point of islands. The suppression of runaway electrons during disruptions is essential to the operation of ITER, and it has been reached by utilizing the 3D magnetic perturbations on J-TEXT. This may provide an alternative mechanism of runaway suppression for large-scale tokamaks and ITER.

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“…In addition, the SMBI can flexibly adjust the quantity of the injected particles, which allows particles with a wide range of quantities to be injected into the plasma by changing the pulse duration and source pressure. Thus, the SMBI system meets the requirements of a situation where numerous particles are required, such as disruption mitigation (Huang et al 2017) and active control of the heat load (Cheng et al 2013;Gao et al 2017).…”

Section: Introductionmentioning

confidence: 99%

A review of supersonic molecular beam injection for plasma fueling and physical studies in magnetic fusion devices

Xiao

Zhong

Duan

et al. 2022

Rev. Mod. Plasma Phys.

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In magnetic confinement fusion devices, supersonic molecular beam injection (SMBI) is commonly used as a fueling method, which has also performed well in physical studies since it was first proposed on the HL-1 tokamak by Southwestern Institute of Physics. This study presents the development of the SMBI technique since its first use in fusion experimental devices and reviews the progress on the investigation of plasma physics using the SMBI. In addition, this study further discusses the potential applications of the SMBI technique on future fusion devices.

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Suppression of runaway current generation by supersonic molecular beam injection during disruptions on J-TEXT

Cited by 11 publications

References 49 publications

Overview of operation and experiments in the ADITYA-U tokamak

Overview of operation and experiments in the ADITYA-U tokamak

Overview of the recent experimental research on the J-TEXT tokamak

A review of supersonic molecular beam injection for plasma fueling and physical studies in magnetic fusion devices

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