H. Y. Wang;W. H. Hu;Y. H. Wang;Y. Huang;Y. H. Jia;Z. P. Luo;R. R. Zhang;Q. P. Yuan;B. J. Xiao
{"title":"A Machine Learning Predictor for Vertical Displacement Events on EAST","authors":"H. Y. Wang;W. H. Hu;Y. H. Wang;Y. Huang;Y. H. Jia;Z. P. Luo;R. R. Zhang;Q. P. Yuan;B. J. Xiao","doi":"10.1109/TPS.2025.3528970","DOIUrl":"https://doi.org/10.1109/TPS.2025.3528970","url":null,"abstract":"To obtain higher discharge parameters in experimental advanced superconducting tokamak (EAST) experiments, an elongated plasma configuration is applied. As a result, vertical displacement events (VDEs) are easy to occur, especially for plasma with high vertical instability growth rate. Studying the prediction and avoidance of VDEs is of great importance for the protection of the plasma-facing and structural components of EAST tokamak. Data-driven methods based on supervised learning are widely used in disruption prediction. Labels as the key of the supervised learning are difficult to accurately divide. In this article, we first propose a labeling method based on the Jensen-Shannon (JS) divergence, enabling a specific analysis and evaluating the precursor onset time for each discharge. By comparing prediction accuracy and warning time prior to disruption using different algorithms with dataset collected from EAST experiment of 2021–2023, it is found that random forest (RF) model works best and achieves a success VDE alarm rate of 99.2% with a false alarm rate of 2.1% for nondisruptive discharges. The results show that models trained with dataset collected with class split point found by the JS divergence method from each discharge outperforms models trained with the dataset collected from each discharge with class split point of fixed time before disruption.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"136-145"},"PeriodicalIF":1.3,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ion Acoustic Waves in Plasma With Perturbation in Ion Temperature","authors":"H. R. Pakzad;K. Javidan","doi":"10.1109/TPS.2025.3528096","DOIUrl":"https://doi.org/10.1109/TPS.2025.3528096","url":null,"abstract":"The behavior of ion acoustic solitary waves (IASWs) in an electron-ion plasma with spatially varying ion temperatures is studied using the reductive perturbation method. In this case, the relative temperature (<inline-formula> <tex-math>$sigma $ </tex-math></inline-formula>) is considered a first-order perturbation. The modified Korteweg-de Vries (mKdV) equation is obtained to describe the wave behavior in which <inline-formula> <tex-math>$sigma $ </tex-math></inline-formula> is a critical parameter of the model. The propagated localized ion-acoustic wave is affected by the temperature perturbation area while the amplitude of the ion acoustic soliton decreases after the interaction with perturbation.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"29-33"},"PeriodicalIF":1.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenchao Li;Yingjie Chen;Youlong Wang;Rongyao Fu;Ping Yan;Yaohong Sun
{"title":"Discharge Characteristics and Launch Experiment of Multiphase Air-Core Pulsed Alternator","authors":"Wenchao Li;Yingjie Chen;Youlong Wang;Rongyao Fu;Ping Yan;Yaohong Sun","doi":"10.1109/TPS.2025.3529314","DOIUrl":"https://doi.org/10.1109/TPS.2025.3529314","url":null,"abstract":"The application of a multiphase air-core pulsed alternator (APA) power supply system in railgun has been studied. First, the working principle of the multiphase APA power supply system driving the railgun is introduced in detail, and the mathematical models of the multiphase APA and the railgun are given. Second, the discharge characteristics of the multiphase APA power supply system are analyzed. The relationship between the load current and the phase current is expounded at the theoretical level, and the characteristics such as the amplitude and pulsewidth of the phase current during the discharge process of the eight-phase motor are analyzed and parsed. Then, a field-circuit coupling simulation model is constructed to simulate and analyze the discharge process of the multiphase APA driving the railgun, verifying the correctness of the theoretical analysis. Finally, the experimental platform of multiphase APA driving the railgun is built, and the launch experiments are successfully conducted. Meanwhile, valuable experimental data are also provided for the subsequent further experiments.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"71-78"},"PeriodicalIF":1.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design and Analysis of Pulse Trigger Source for Triggered Vacuum Switch Based on Pulse Transformer","authors":"Liang Bu;Xubin Li;Minfu Liao;Ming Zhang;Gang Lu;Longfei Yu;Xiongying Duan","doi":"10.1109/TPS.2024.3525131","DOIUrl":"https://doi.org/10.1109/TPS.2024.3525131","url":null,"abstract":"Field breakdown triggered vacuum switch (FTVS) has higher requirements for triggering pulse. The trigger source based on pulse transformer and solid-state switch has good reliability and low jitter characteristics, which can be used to trigger FTVS. A detailed analysis of the working process of the trigger source is beneficial for better design of the trigger source. This article introduces the analysis and the design process of a pulse trigger source (PTS) based on a pulse transformer using a closed annular magnetic core and IGBT. An analytical analysis of the main working process of the PTS is provided, and the effects of the PTS’s stray resistances, leakage inductances, and distributed capacitances on the output pulse waveform are evaluated. By optimizing the structure of the pulse transformer and selecting appropriate magnetic core materials, the response characteristics of the pulse transformer have been improved. The experimental results demonstrate the effectiveness of the proposed analysis presented in this article. The designed PTS can generate high-voltage pulses with peak values exceeding 18 kV, pulsewidth of <inline-formula> <tex-math>$0sim 5~mu $ </tex-math></inline-formula>s, and rise time of <560 ns, which can reliably trigger FTVS.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"79-87"},"PeriodicalIF":1.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jingyi Lin;Jianwen Wu;Shangwen Xia;Ruang Chen;Mingshun Ma
{"title":"Multiobjective Optimization of Key Parameters for the Chamber of Low-Voltage DC Circuit Breakers Based on MHD","authors":"Jingyi Lin;Jianwen Wu;Shangwen Xia;Ruang Chen;Mingshun Ma","doi":"10.1109/TPS.2025.3528424","DOIUrl":"https://doi.org/10.1109/TPS.2025.3528424","url":null,"abstract":"The extinguishing performance of low-voltage dc circuit breakers is intricately influenced by the arc motion process, which in turn is shaped by the structure of the arc chamber. Consequently, optimizing and refining the arc chamber structure is imperative for augmenting arc-extinguishing efficacy. Addressing this necessity, this study presents an advanced multiobjective optimization algorithm grounded in the magnetohydrodynamic (MHD) model for low-voltage dc circuit breakers. The optimization targets key geometrical parameters within the chamber, encompassing the arc runner length, splitter plate inclination angle, as well as the horizontal and vertical spacing between neighboring splitter plates, to minimize both arc energy and overvoltage. Relative coefficients for primary and secondary objectives are seamlessly integrated into the optimization process to bolster computational efficiency. Leveraging simulation models, this algorithm expeditiously explores the impact of various arc chamber structural parameters on arc motion, thereby furnishing invaluable insights for designing and optimizing low-voltage circuit breakers.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"88-98"},"PeriodicalIF":1.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of the Electron Distribution Function Inside of a LaB₆ Hollow Cathode","authors":"Kirk J. Boehm;James D. Rogers;Richard D. Branam","doi":"10.1109/TPS.2025.3527476","DOIUrl":"https://doi.org/10.1109/TPS.2025.3527476","url":null,"abstract":"Langmuir probe measurements have been performed many times in hollow cathodes and remain one of the most commonly used diagnostic methods to determine electron temperature, density, and plasma potential. The objective of this project was to analyze which possible electron processes can also be determined using a single-wire Langmuir probe in combination with the Druyvesteyn electron energy distribution function (EEDF) method. The well-documented JPL NASA LaB6 hollow cathode using argon, without a heater and without an orifice, was chosen for this study. The probe tip was located at the backend of the plasma. The Druyvesteyn EEDF method resulted in three distinct electron population peaks, representing single ionization, secondary electron production due to ion bombardment of the low work function insert, and thermionic electron production. The electron temperature for almost all three peaks decreased slightly with increasing mass flow rate. The electron number density also decreased with mass flow rate; however, each population showed a different rate of decrease. The detection showed different populations for different locations in the upstream plasma sheath. The results of this investigation indicate that thermionic emission, secondary ion bombardment, ionization, and their associated electron extractions can be measured using the Druyvesteyn EEDF method.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"63-70"},"PeriodicalIF":1.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparative Analysis of Radial Plasma Parameters and Electric Field Shear With and Without the Edge Transport Barrier Formation in SSDT Devices","authors":"Kamal M. Ahmed;A. H. Bekheit;M. M. Abdelrahman","doi":"10.1109/TPS.2025.3527373","DOIUrl":"https://doi.org/10.1109/TPS.2025.3527373","url":null,"abstract":"In magnetic confinement reactors, the radial electric field and its shear are very important for edge transport barrier (ETB) formation and turbulence suppression. In the present work, a multifluid transport code, B2SOLPS5.02D, was used to model the radial distribution of plasma parameters (such as electron density, electron temperature, and ion velocity), radial electric field, and its shear in both cases with and without the ETB formation in small size divertor tokamak (SSDT) devices. The results demonstrated that the radial electric field in the ETB mode is similar to the neoclassical electric field near the separatrix. A toroidal rotation was observed in the co-current/counter-current directions in the discharge without/with the ETB, respectively. An intense radial electric field shear developed, resulting in a significant reduction in the transport coefficient. The ETB region appeared to be located between the maximum and minimum values of the radial electric field shear. Furthermore, the results demonstrated that the ETB width was proportional to the ion temperature and inversely proportional to the radial electric field shear. The impact of the radial electric field shear on the diffusion coefficient, plasma density, and ETB formation was investigated.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"122-135"},"PeriodicalIF":1.3,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A G-Band Traveling Wave Tube Based on Mode Selection Circuit for Suppressing Backward Wave Oscillation","authors":"Zechuan Wang;Zhigang Lu;Peng Gao;Li Qiu;Jingrui Duan;Zhanliang Wang;Shaomeng Wang;Yuan Zheng;Huarong Gong;Yubin Gong","doi":"10.1109/TPS.2024.3524420","DOIUrl":"https://doi.org/10.1109/TPS.2024.3524420","url":null,"abstract":"To suppress the backward wave oscillations in traveling wave tube (TWT) amplifiers, which are caused by the high gain of higher-order modes, mode selective folded waveguide (MSFW) is proposed as a slow wave structure (SWS). The MSFW consists of folded waveguide (FW) and mode selective circuit (MSC). Specifically, the MSC is made up of two segments of discontinuous rectangular waveguides. Consequently, the MSC can realize the suppression of the higher-order modes of the FW effectively and thus improve the performance of the FW-TWT. The simulation results show that the single-segment MSFW-TWT has a 3-dB bandwidth of 212.5–218.5 GHz, a saturated output power of more than 72 W, and a maximal gain of 39.59 dB. Meanwhile, the risk of the TWT’s backward wave oscillations is greatly reduced. As a result, the great potential of MSFW as a terahertz (THz) amplifier can be clearly seen from these results.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"146-152"},"PeriodicalIF":1.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigation on Large-Amplitude Ion-Acoustic Shock in Negative Ion Plasma","authors":"Pallabi Pathak;H. Bailung","doi":"10.1109/TPS.2024.3522894","DOIUrl":"https://doi.org/10.1109/TPS.2024.3522894","url":null,"abstract":"Evolution of large-amplitude ion-acoustic shock in plasma containing electrons, <inline-formula> <tex-math>$text {Ar}^{+}$ </tex-math></inline-formula> and <inline-formula> <tex-math>$text {F}^{-}$ </tex-math></inline-formula> ions, has been investigated. As for the extremely high-amplitude shock wave in multicomponent plasma with negative ions, we achieved a density perturbation of ~70%, in contrast to the ~15% density perturbation observed in an electron-ion plasma. The numerical results of well-known Korteweg-de Vries (KdV)–Burger equation were employed in order to compare our exquisite observations. Furthermore, we explore the impact of enhanced Landau damping on the large-amplitude shocks in the plasma containing negative ions. The negative-to-positive ion density ratio is kept at approximately <inline-formula> <tex-math>$r(=n_{-}{/}{n}_{+})sim 0.25$ </tex-math></inline-formula>.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 1","pages":"3-11"},"PeriodicalIF":1.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}