Minor disruptions triggered by supersonic molecular beam injection on J-TEXT tokamak

Jiang, Zhonghe; Yang, Tong; Yuan, Jianjun; Li, C.H.; Ye, X.; Huang, Junjie; Liang, Y.; Izzo, V.A.; Huang, Mingxiang; Tong, R. H.; Huang, Yuan; Cai, Qinxue; Yan, Xiaodong; Zhu, Lizhi; Yang, Zhoujun; Ding, Yonghua; Zhu, Ping; Chen, Zhiyi; Team, and J-Text

doi:10.1088/1741-4326/ab7d19

Cited by 6 publications

(4 citation statements)

References 38 publications

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“…The simulation results imply that the impurity is easier to spread into the core region with smaller phase difference of ∆θ between the peak value of ionized Ar density and the peak value of V r . Unlike our previous research work, [33] the impurity transport mechanism here is more likely to come from 𝐸 × 𝐵 perpendicular convection of plasma and leads to the radial flow of impurities. However, to clarify the final transport mechanism, we need to further analyze the generation mechanism of radial flow under the condition of preseeded multi-modes, this is our next work.…”

Section: Discussionmentioning

confidence: 68%

Effect of the relative phase between pre-existing 2/1 and 3/1 magnetic islands on the suppression of runaway electrons on J-TEXT

Xiong

Jiang²,

Jiao³

et al. 2023

Chinese Phys. B

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In the experiments of actively triggering plasma disruption by massive gas injection, the externally applied resonant magnetic perturbation has been used to mitigate the hazard of runaway electron (RE). Motivated by the experiment of multimode coupling to suppress REs on J-TEXT, some typical simulation cases with NIMROD (Non-Ideal MHD with Rotation-Open Discussion) code are carried out to explore the influential mechanism of different relative phases between m/n = 2/1 and m/n = 3/1 magnetic islands on the confinement of REs. Results show that the RE confinement is drastically affected by the relative phase between 2/1 and 3/1 magnetic islands. When the “O point” phase of 2/1 and 3/1 magnetic islands is toroidal 330°, REs can be effectively lost. The fitting curve of the remaining ratio of REs vs. the relative toroidal phase is predicted to approximate a sine-like function dependence. Further studies indicate that the phase difference between coexisting 2/1 and 3/1 islands can affect the radial transport of impurities. The loss of runaway electrons is closely related to the deposition effect of impurity. The impurity is easier to spread into the core region with smaller poloidal phase difference between the radial velocity of impurity and the impurity quantity of Ar.

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Section: Discussionmentioning

confidence: 68%

Effect of the relative phase between pre-existing 2/1 and 3/1 magnetic islands on the suppression of runaway electrons on J-TEXT

Xiong

Jiang²,

Jiao³

et al. 2023

Chinese Phys. B

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“…Another possible reason is that the flow triggered by E × B can lead to the enhancement of radial transport. However, as shown in our former work [36], the evidence for the significant increase in radial flow at the time of magnetic perturbation enhancement is insufficient.…”

Section: Computational Modelmentioning

confidence: 63%

“…The location of neutral impurity source is the bottom port on J-TEXT. The MGI model has been used in simulations to analyze MGI experiments in J-TEXT [36].…”

Section: Computational Modelmentioning

confidence: 99%

The effect of 2/1 pre-existing magnetic islands width on the suppression of runaway electrons in disruption simulations of J-TEXT

Jiang

Lin

et al. 2020

Plasma Phys. Control. Fusion

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The suppression of runaway electrons (REs) is influenced by the size of pre-existing 2/1 magnetic islands. Simulations of argon (Ar) massive gas injection into J-TEXT plasmas with pre-existing 2/1 magnetic islands of different width are performed with the 3D magnetohydrodynamic code called NIMROD (Sovinec et al 2004 J. Comput. Phys. 195 355). Results show that the ratio of remaining REs is not monotonically dependent on the width of pre-existing 2/1 magnetic islands. Large enough pre-existing 2/1 magnetic islands can lead to strong magnetic perturbation and strong magnetic surface stochasticity to expel the REs. The critical width for the suppression of REs is to be 0.31 as the minor radius. Under the condition of suitable small pre-existing 2/1 magnetic islands width, with island width ranging from 0.07 to 0.11 times the minor radius, the mitigation of REs is achieved. The duration of magnetic perturbations δB/B(n = 1) (exceeding (4 to 6) × 10 −3 ) is a key for RE loss, and high amplitude of high n modes plays an important role in RE loss.

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“…been reported in the J-TEXT tokamak [39]. The density evolution at the core of one of the successful shots (shot #31271) is show in figure 7.…”

Section: Statistics and Comparison Of Successful And Unsuccessful Re ...mentioning

confidence: 95%

Runaway electron mitigation with supersonic molecular beam injection (SMBI) in ADITYA-U tokamak

Banerjee¹,

Singh²,

Raj³

et al. 2020

Nucl. Fusion

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The generation and subsequent loss of runaway electrons (REs) during the operation sequence in a tokamak is a potent threat to the plasma-facing components and the interface of actively cooled parts. Control and mitigation of REs are of prime importance to the safe operation and machine health of a fusion device. A supersonic molecular beam injection (SMBI) system has been installed in the ADITYA-U tokamak to explore the effects of the high Mach number molecular beam on the REs and ways to mitigate the REs. In the majority of discharges in which SMBI has been injected, a burst in hard x-rays has been observed accompanying the SMBI pulse, indicating significant RE loss. This is followed by a long RE-mitigated phase in the discharge. The most plausible explanation of the mitigation of REs is minor disruption caused by SMBI. This in turn triggers field line stochastization and subsequent rapid RE loss. Finally, this leads to reorganization of the flux surfaces, resulting in bigger islands with the potential of trapping any surviving RE fraction.

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Minor disruptions triggered by supersonic molecular beam injection on J-TEXT tokamak

Cited by 6 publications

References 38 publications

Effect of the relative phase between pre-existing 2/1 and 3/1 magnetic islands on the suppression of runaway electrons on J-TEXT

Effect of the relative phase between pre-existing 2/1 and 3/1 magnetic islands on the suppression of runaway electrons on J-TEXT

The effect of 2/1 pre-existing magnetic islands width on the suppression of runaway electrons in disruption simulations of J-TEXT

Runaway electron mitigation with supersonic molecular beam injection (SMBI) in ADITYA-U tokamak

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