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Influence of 3D helical magnetic perturbations on runaway electron generation in J-TEXT tokamak

Plasma Science and technology 2025年第3期27卷 36-44页

作者： Wei YAN Guinan ZOU Zhongyong CHEN You LI Jiangang FANG Zhifang LIN Zhonghe JIANG Nengchao WANG Bo RAO Yangbo LI Zhengkang REN Chuanxu ZHAO Yu ZHONG Fanxi LIU Yinlong YU Zisen NIE Xun ZHOU Yuan SHENG Yuwei SUN Song ZHOU Xiaoqing ZHANG Zhoujun YANG Zhipeng CHEN Yonghua DING the J-TEXT Team State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma PhysicsSchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China School of Electrical Engineering&Automation Jiangsu Normal UniversityXuzhou 221116People’s Republic of China 不详

A large number of runaway electrons(REs)generated during disruption can cause significant damage to next-generation large-scale *** influence of three-dimensional(3D)helical magnetic perturbations on the suppression of RE generation was explored using a set of 3D helical coils in J-TEXT tokamak,which can excite m/n=-2/2 helical magnetic *** evidence shows that the-2/2 magnetic perturbations caused by the opposite coil current direct plasma toward the high-field side,simultaneously enhancing the magnetic fluctuations,which would enhance the radial loss of REs and even prevent RE *** the other hand,-2/2 magnetic perturbations can also reduce the cooling time during the disruption phase and generate a population of high-energy REs,which can interact with high-frequency magnetic fluctuations and in turn suppress RE *** critical helical coil current was found to correlate with electron density,requiring higher coil currents at higher *** to the statistical analysis of RE generation at different electron densities,the applied-2/2 magnetic perturbations can increase the magnetic fluctuations to the same level at lower electron densities,which can decrease the threshold electron density for RE *** will be beneficial for RE mitigation in future large tokamak devices.

关键词： 3D helical magnetic perturbations runaway electron J-TEXT tokamak

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Optimization Design of Coated Armature in electromagnetic Railgun Based on Multi-objective Genetic Algorithm 10

Optimization Design of Coated Armature in Electromagnetic Ra...

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10th Euro-Asian Pulsed Power Conference, 25th International Conference on High-Power Particle Beams and 20th International Symposium on electromagnetic Launch technology, EAPPC-BEAMS-EML 2024

作者： Xu, Xuan Chen, Lixue Xu, Shengqin Zhang, Wenhao Zhao, Bingxuan Xiao, Tingyun Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9789038661353

The electromagnetic railgun is an advanced launch device that accelerates the armature to ultra-high speed through electromagnetic force. The contact between the armature and the two rails is a kind of ultimate sliding electrical contact beyond high pulse current, high speed, and high contact pressure. It leads to excessive local electromagnetic field distribution at the contact interface, which is not conducive to launch performance. In this paper, armatures of different coated structures are considered to improve the electromagnetic field distribution. First, the characteristic-difference scheme based on the bilinear interpolation method is presented to solve the electromagnetic governing equation of the railgun when launching armatures of different coated structures. Second, an optimization design based on NSGA-II is constructed to obtain the Pareto optimal solution set, and an optimized armature of coated structure that brilliantly meets the design objectives is selected. Finally, numerical calculations are conducted based on the optimized parameters to verify the effectiveness of the multimaterial coated armature structure. Results show that the maximum current density of the optimized armature is reduced by 54% compared to the uncoated armature, current diffusion time at the contact interface along the x-direction is shortened by 80 μs, and the penetration depth of the current along the ydirection at the armature-rail contact interface is increased by 1.6 mm, which significantly optimizes the current distribution during the launch process of the electromagnetic railgun. © 2024 Eindhoven University of technology.

关键词： Multiobjective optimization

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Disruption prediction based on fusion feature extractor on J-TEXT

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Chinese Physics B 2023年第7期32卷 12-23页

作者：郑玮薛凤鸣陈忠勇沈呈硕艾鑫坤钟昱王能超张明丁永华陈志鹏杨州军潘垣 International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Institute of Artificial Intelligence Huazhong University of Science and TechnologyWuhan 430074China

Predicting disruptions across different tokamaks is necessary for next generation *** large-scale tokamaks can hardly tolerate disruptions at high performance discharge,which makes it difficult for current data-driven methods to obtain an acceptable result.A machine learning method capable of transferring a disruption prediction model trained on one tokamak to another is required to solve the *** key is a feature extractor which is able to extract common disruption precursor traces in tokamak diagnostic data,and can be easily transferred to other *** on the concerns above,this paper presents a deep feature extractor,namely,the fusion feature extractor(FFE),which is designed specifically for extracting disruption precursor features from common diagnostics on ***,an FFE-based disruption predictor on J-TEXT is *** feature extractor is aimed to extracting disruption-related precursors and is designed according to the precursors of disruption and their representations in common tokamak *** inductive bias on tokamak diagnostics data is *** paper presents the evolution of the neural network feature extractor and its comparison against general deep neural networks,as well as a physics-based feature extraction with a traditional machine learning *** demonstrate that the FFE may reach a similar effect with physics-guided manual feature extraction,and obtain a better result compared with other deep learning methods.

关键词： feature extractor disruption prediction deep learning tokamak diagnostics

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Multi-objective Optimization Method of arc Armature Based on Anti-Transition 19th

Multi-objective Optimization Method of arc Armature Based on...

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19th Annual Conference of China Electrotechnical Society, ACCES 2024

作者： Gu, Anbang Xia, Shengguo Key Laboratory of Pulsed Power Technology Ministry of Education Huazhong University of Science and Technology Wuhan China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9789819608966

Three optimization objectives are proposed to suppress transition during the armature launching process: the deviation rate of the current density distribution on the armature rail’s contact surface under steady-state current, the deviation rate of the current density distribution on the throat’s surface under steady-state current, and the deviation degree of the overfill contact pressure’s center of action. The NSGA-2 multi-objective optimization algorithm is used to optimize the armature structure. Firstly, the random response surface of the optimization objectives is established in a large range of armature geometrical parameters, and then the range of values of armature geometrical parameters is obtained according to the limitations of the armature structure in the actual problem, and then the optimization of the armature structure is carried out and the optimal compromise solution is screened out in this range. The simulation results show that the optimized armature, compared with the benchmark armature, has a more centered distribution of the overfill contact pressure on the contact surface, smaller current peaks on the contact surface of the armature rails during the launching process, and lower maximum temperature at the throat, which indicates that the optimized armature is more capable of suppressing the armature start-up phase transition, the magnetic saw of the throat transition, and the current falling-edge phase transition. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Multiobjective optimization

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Revealing the size effect of Fe S2on solid-state battery performances at different operating temperatures

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Chinese Chemical Letters 2024年第6期35卷 189-194页

作者： Chaochao Wei Ru Wang Zhongkai Wu Qiyue Luo Ziling Jiang Liang Ming Jie Yang Liping Wang Chuang Yu School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China

FeS_(2) shows significant potential as cathode material for all-solid-state lithium batteries(ASSLBs)due to its high theoretical specific capacity,low cost,and environmental ***,the poor ion/electron conductivity and large volume variation effect of FeS_(2) inhibit its practical ***,the influence of particle size of FeS_(2) on the corresponding sulfide-based solid-state batteries is carefully investigated by tuning FeS_(2) ***,low operating temperature is chosen to mitigate the large volume changes during cycling in the battery.S-FeS_(2) with smaller particle sizes delivers superior electrochemical performances than that of the larger L-FeS_(2) in Li_(5.5)PS_(4.5)Cl_(1.5)-based ASSLBs under different operating temperatures.S-FeS_(2) shows stable discharge capacities during 50 cycles with a current density of 0.1 m A/cm^(2)under -20℃.When the current density rises to 1.0 m A/cm^(2),it delivers an initial discharge capacity of 146.9 m Ah/g and maintains 63% of the capacity after 100 *** work contributes to constructing ASSLBs enables excellent electrochemical performances under extreme operating temperatures.

关键词： FeS_(2) Size effect Li_(5.5)PS_(4.5)Cl_(1.5) electrolytes Operating temperatures Electrochemical performances

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Multiple discharges before leader inception in long air gaps under positive switching impulses

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High Voltage 2023年第1期8卷 111-118页

作者： Xiangen Zhao Juhyeong Lee Gang Liu Lei Jia Yang Liu Junjia He Yaping Du Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityHung HomHong KongChina Department of Mechanical and Aerospace Engineering Utah State UniversityLoganUtahUSA State Key Laboratory of HVDC Transmissions Technology Electric Power Research InstituteChina Southern Power GridGuangzhouChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhanChina

There are multiple corona bursts before leader inception when the rising rate of the applied voltage or electric field is not sufficiently high enough in long positive *** existing studies,no attention has been paid to whether these corona bursts occur in the same location,and they are mostly considered directly as belonging to the same ***,this paper presents that in a typical rod-plate long air gap,the multiple corona bursts before leader inception are distributed in at least two different locations,and the highest probability of three discharges ***,the discharge occurs with the highest probability in the time sequence‘tip-tip-side-tip-other side’of the electrode in the first five corona *** each discharge,the first corona current is a single,double exponential pulse,while the following corona currents are mostly a superposition of multiple *** above findings are mainly based on experiments in a 1.4 m air gap under positive switching impulses,in which the voltage,current,and high-speed images were recorded ***,based on the experimental results,this paper discusses the effects brought by ignoring the multiple discharges on key parameters of leader inception and makes some suggestions to optimise long spark experiments.

关键词： positive exponential superposition

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Influence of arc armature geometric parameters on current distribution at the armature/guideway interface 10

Influence of arc armature geometric parameters on current di...

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10th Euro-Asian Pulsed Power Conference, 25th International Conference on High-Power Particle Beams and 20th International Symposium on electromagnetic Launch technology, EAPPC-BEAMS-EML 2024

作者： Chen, Lixue Zhao, Bingxuan You, Penghao Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9789038661353

In this paper, a parametric model of arc armature is established. And simulation models considering velocity skinning effect and pre-contact resistance are also established in this paper using COMSOL. Through this model, the effects of each parameter of the armature on the current distribution at the armature-rail interface are investigated, and by processing the results, the effects of different parameters on the current distribution at the armature-rail interface are compared. It is shown that the curvature of the arc surface, the amount of internal retraction and the length of the tailplane have the greatest influence on the current distribution at the armature-rail interface. © 2024 Eindhoven University of technology.

关键词： electromagnetic launchers

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Launch Efficiency of Capacitive Energy-Storage electromagnetic Railgun System 10

Launch Efficiency of Capacitive Energy-Storage Electromagnet...

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10th Euro-Asian Pulsed Power Conference, 25th International Conference on High-Power Particle Beams and 20th International Symposium on electromagnetic Launch technology, EAPPC-BEAMS-EML 2024

作者： Xiao, Tingyun Chen, Lixue Xu, Xuan Xu, Shengqin Zhang, Wenhao Zhao, Bingxuan Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9789038661353

electromagnetic railgun have high initial velocity, long range and other advantages. Improving the launch efficiency is one of the most important needs for the application of electromagnetic rail launch technology. Based on the subsystem models of pulse power supply, rail and armature of railgun, the equivalent circuit mathematical model of the electromagnetic rail gun system under lumped parameters is established. The effects of capacitance, voltage, inductance, resistance and acceleration distance on the system efficiency were simulated and analyzed. The results of the study are of great significance in guiding the design of the electromagnetic launch system. © 2024 Eindhoven University of technology.

关键词： Rail guns

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Effect of surface morphology on armature melt wear 10

Effect of surface morphology on armature melt wear

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10th Euro-Asian Pulsed Power Conference, 25th International Conference on High-Power Particle Beams and 20th International Symposium on electromagnetic Launch technology, EAPPC-BEAMS-EML 2024

作者： Zhao, Bingxuan Chen, Lixue Xu, Shengqin Xu, Xuan Zhang, Wenhao Xiao, Tingyun Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9789038661353

Armature melting during electromagnetic launch affects the electrical contact characteristics between armature and rail, which in turn affects the launching process and the service life of the launcher. A coupled multi-physics field model considering rough surfaces is constructed. Based on this, the influence law on armature erosion characteristics is *** results show that the higher the armature surface characteristic scale factor the lower the overall armature temperature, the later the melting onset time, but the more uneven armature surface melting;the higher the surface fractal dimension the less armature melting. The results provide a reference for the optimization of armature surface processing. © 2024 Eindhoven University of technology.

关键词： Fractal dimension

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Online Multiparameter Estimation with Position Error Correction for Unified Synchronous Machine Sensorless Drives

Online Multiparameter Estimation with Position Error Correct...

引用

2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023

作者： Liu, Zirui Kong, Wubin Fan, Xinggang Wang, Fei Qu, Ronghai Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9798350316445

Parameters' accuracies are essential for model-based sensorless control in synchronous machine drives. In this paper, a multiparameter adaptive observer and a position error optimizer are presented to obtain real-time parameter information in the absence of rotor position data for unified synchronous machine (SM). The adaptive observer is based on the misaligned dq-axes' small-signal impedance model where dq-axes EMF coupling terms are well considered. All parameters can achieve high accuracy under entire operation region. In the case of isotropic SMs, the estimated parameters can be directly utilized in the model-based observer to acquire high precision position observation. And, for anisotropic SMs, an optimizer is introduced to correct parameter inaccuracies caused by position error. The effectiveness of the proposed adaptive observer and optimizer is evaluated through a combination of experiments and simulations, providing comprehensive validation of their performance. © 2023 IEEE.

关键词： Multiparameter Estimation Sensorless Control Unified Synchronous Machine (SM)

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