Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3485051
Akira Daibo;Yoshimitsu Niwa;Yo Sasaki;Takuya Saito;Takeshi Yoshida
In vacuum interrupters, plasma remains between the electrodes after the current zero because of arcs generated by the interruption of short-circuit current. This residual plasma consisting of ions, electrons, and metal vapor affects the insulation recovery process after the short-circuit current interruption. The ion and electron densities can be attributed to the post-arc current and the electrode surface temperature. Therefore, direct measurement of the post-arc current and electrode surface temperature is crucial for a fundamental understanding of the insulation recovery process after the short-circuit current interruption. In this study, a prototype spiral electrode was mounted in a vacuum chamber, and the electrode surface temperature and the post-arc current were measured. The electrode was made of Cu-Cr material, and the interruption current above 10–24 kArms was applied. The electrode surface temperature was measured two-dimensionally using a two-color pyrometer method. The melting area increased with an increase in the interruption current above 20 kArms. The post-arc current and its charge also increased with increasing the interruption current, but they did not increase as dramatically as the melting area.
{"title":"Measurement of Electrode Surface Temperature and Post-Arc Current in Vacuum Interrupter","authors":"Akira Daibo;Yoshimitsu Niwa;Yo Sasaki;Takuya Saito;Takeshi Yoshida","doi":"10.1109/TPS.2024.3485051","DOIUrl":"https://doi.org/10.1109/TPS.2024.3485051","url":null,"abstract":"In vacuum interrupters, plasma remains between the electrodes after the current zero because of arcs generated by the interruption of short-circuit current. This residual plasma consisting of ions, electrons, and metal vapor affects the insulation recovery process after the short-circuit current interruption. The ion and electron densities can be attributed to the post-arc current and the electrode surface temperature. Therefore, direct measurement of the post-arc current and electrode surface temperature is crucial for a fundamental understanding of the insulation recovery process after the short-circuit current interruption. In this study, a prototype spiral electrode was mounted in a vacuum chamber, and the electrode surface temperature and the post-arc current were measured. The electrode was made of Cu-Cr material, and the interruption current above 10–24 kArms was applied. The electrode surface temperature was measured two-dimensionally using a two-color pyrometer method. The melting area increased with an increase in the interruption current above 20 kArms. The post-arc current and its charge also increased with increasing the interruption current, but they did not increase as dramatically as the melting area.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4396-4401"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798043","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3486335
Xiaojing Ren;Weihua Jiang;Jingming Gao;Hanwu Yang
Hybrid energy storage (HES) is a new approach that combines capacitive energy storage (CES) and inductive energy storage (IES), and parallel HES (P-HES) is one of the most basic structures of the HES method. As the name suggests, P-HES refers to that a capacitor and an inductor are connected in parallel to discharge. Its operation is controlled by power devices, so due to the controllability, the adjustability of P-HES circuits can be achieved. In this study, we first elucidated the principles and basic characteristics through the simulation on one P-HES module. Then, a P-HES experimental platform was built based on SiC MOSFETs and the feasibility of its operation was verified through experiments. After that, we proposed two superimposed topologies, which can achieve voltage adding, one is modular circuit and the other is a simplified circuit. As a result, the feasibility of these two superimposed circuit structures is experimentally demonstrated, and their output consistency is also evident. In addition, the miniaturization of the simplified three-stage circuit has been achieved through the three-series design of the switching unit.
{"title":"Pulsed Power Generation Circuit Based on Parallel Hybrid Energy Storage","authors":"Xiaojing Ren;Weihua Jiang;Jingming Gao;Hanwu Yang","doi":"10.1109/TPS.2024.3486335","DOIUrl":"https://doi.org/10.1109/TPS.2024.3486335","url":null,"abstract":"Hybrid energy storage (HES) is a new approach that combines capacitive energy storage (CES) and inductive energy storage (IES), and parallel HES (P-HES) is one of the most basic structures of the HES method. As the name suggests, P-HES refers to that a capacitor and an inductor are connected in parallel to discharge. Its operation is controlled by power devices, so due to the controllability, the adjustability of P-HES circuits can be achieved. In this study, we first elucidated the principles and basic characteristics through the simulation on one P-HES module. Then, a P-HES experimental platform was built based on SiC MOSFETs and the feasibility of its operation was verified through experiments. After that, we proposed two superimposed topologies, which can achieve voltage adding, one is modular circuit and the other is a simplified circuit. As a result, the feasibility of these two superimposed circuit structures is experimentally demonstrated, and their output consistency is also evident. In addition, the miniaturization of the simplified three-stage circuit has been achieved through the three-series design of the switching unit.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4648-4654"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797928","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3424897
Braj Kishore Shukla;Joydeep Ghosh;D. Raju;R. L. Tanna;Vipul Tanna;Upendra Prasad;Jatin Patel;Harshida Patel;Dharmesh Purohit;Mahesh Kushwah;S. K. Pathak;P. K. Atrey;Hardik Mistry;K. G. Parmar;Manoj Gupta;Ranjana Manchanda;Kiti Mahajan;Aveg Chauhan;D. Raval;Rohit Kumar;Suman Aich;K. A. Jadeja;K. M. Patel;Harshita Raj;Tanmay Macwan;V. Balakrishnan;Shivam Gupta;M. N. Makwana;K. S. Shah;C. N. Gupta;M. B. Chowdhuri;Umesh Nagora;Varsha Siju;Jayesh Raval;K. Tahiliani;Pramila Gautam;E. V. Praveenlal;P. K. Chattopadhyay
Electron cyclotron resonance heating (ECRH) two-pulse experiments are carried out on the tokamaks SST-1 and Aditya-U using single 42-GHz gyrotron. Initially, the system was used to carry out either breakdown or heating. A new anode modulator power supply with fast rise time and fall time (1 ms) has been integrated with 42-GHz gyrotron system, which facilitate to switch the gyrotron for more than one pulse within plasma shot. The first pulse is used for the plasma breakdown at low-loop voltage and second pulse is used for plasma heating. The power in the first pulse is maintained low (less than 150 kW) for the breakdown at fundamental harmonic, while power in the second pulse is more than 200 kW for plasma heating. In both the tokamaks, SST-1 and Aditya-U, two pulse experiments have been carried out and heating effect is observed clearly in Aditya-U tokamak during second ECRH pulse. This article discusses about the two ECRH pulse experiments on both the tokamaks SST-1 and Aditya-U.
{"title":"ECRH Two-Pulse (Breakdown and Heating) Experiments on Tokamaks Aditya-U and SST-1","authors":"Braj Kishore Shukla;Joydeep Ghosh;D. Raju;R. L. Tanna;Vipul Tanna;Upendra Prasad;Jatin Patel;Harshida Patel;Dharmesh Purohit;Mahesh Kushwah;S. K. Pathak;P. K. Atrey;Hardik Mistry;K. G. Parmar;Manoj Gupta;Ranjana Manchanda;Kiti Mahajan;Aveg Chauhan;D. Raval;Rohit Kumar;Suman Aich;K. A. Jadeja;K. M. Patel;Harshita Raj;Tanmay Macwan;V. Balakrishnan;Shivam Gupta;M. N. Makwana;K. S. Shah;C. N. Gupta;M. B. Chowdhuri;Umesh Nagora;Varsha Siju;Jayesh Raval;K. Tahiliani;Pramila Gautam;E. V. Praveenlal;P. K. Chattopadhyay","doi":"10.1109/TPS.2024.3424897","DOIUrl":"https://doi.org/10.1109/TPS.2024.3424897","url":null,"abstract":"Electron cyclotron resonance heating (ECRH) two-pulse experiments are carried out on the tokamaks SST-1 and Aditya-U using single 42-GHz gyrotron. Initially, the system was used to carry out either breakdown or heating. A new anode modulator power supply with fast rise time and fall time (1 ms) has been integrated with 42-GHz gyrotron system, which facilitate to switch the gyrotron for more than one pulse within plasma shot. The first pulse is used for the plasma breakdown at low-loop voltage and second pulse is used for plasma heating. The power in the first pulse is maintained low (less than 150 kW) for the breakdown at fundamental harmonic, while power in the second pulse is more than 200 kW for plasma heating. In both the tokamaks, SST-1 and Aditya-U, two pulse experiments have been carried out and heating effect is observed clearly in Aditya-U tokamak during second ECRH pulse. This article discusses about the two ECRH pulse experiments on both the tokamaks SST-1 and Aditya-U.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4534-4537"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810616","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}
In this article, a quasi-reflectionless (QR) bandpass filtering power divider (FPD) that features ultrawideband (UWB) performance utilizing low-temperature cofired ceramics (LTCCs) technology is presented. Good QR performance is achieved by the absorptive bandstop filtering (ABSF) section formed with a T-shaped microstrip structure and an absorptive resistor. The wide passband and excellent power division are achieved by utilizing a simple three-line coupled structure (TLCS). Moreover, the employment of LTCC technology enables the arrangement of these sections across multiple layers to achieve a compact size. Finally, to facilitate measurement, we design and fabricate a testing fixture. The measured results demonstrate that our FPD operates at a center frequency of 6.8 GHz, achieving a fractional bandwidth (FBW) of 64.7%. It exhibits QR characteristics from 1 to 13 GHz, with a size of only $10times 6times 0.6$ mm3.
{"title":"An Ultrawideband Quasi-Reflectionless Filtering Power Divider Based on LTCC Technology","authors":"Yukun Li;Dongxu Wang;Weijun Wu;Jianzhong Chen;Kai-Da Xu","doi":"10.1109/TPS.2024.3487172","DOIUrl":"https://doi.org/10.1109/TPS.2024.3487172","url":null,"abstract":"In this article, a quasi-reflectionless (QR) bandpass filtering power divider (FPD) that features ultrawideband (UWB) performance utilizing low-temperature cofired ceramics (LTCCs) technology is presented. Good QR performance is achieved by the absorptive bandstop filtering (ABSF) section formed with a T-shaped microstrip structure and an absorptive resistor. The wide passband and excellent power division are achieved by utilizing a simple three-line coupled structure (TLCS). Moreover, the employment of LTCC technology enables the arrangement of these sections across multiple layers to achieve a compact size. Finally, to facilitate measurement, we design and fabricate a testing fixture. The measured results demonstrate that our FPD operates at a center frequency of 6.8 GHz, achieving a fractional bandwidth (FBW) of 64.7%. It exhibits QR characteristics from 1 to 13 GHz, with a size of only \u0000<inline-formula> <tex-math>$10times 6times 0.6$ </tex-math></inline-formula>\u0000 mm3.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4570-4575"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797917","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3443334
Dun Qian;Zhigang Liu;Xinxin Wang;Xiaobing Zou;Yifan Wang
An energy-efficient method is developed to generate shock wave (SW) from underwater electrical wire-array explosion. By changing the wire connection of cylindrical wire array, parallel is found usually not the suitable connection of wire array to generate SW at a fixed energy. The suitable connection of wire array is determined by initial energy. At a given initial energy, resistance matching between load and external resistance is an important factor to generate a SW, and the corresponding discharge current is critically damped discharge.
{"title":"Enhancement of Shock Wave From Underwater Electrical Wire-Array Explosion at a Fixed Energy by Changing Wire Connection","authors":"Dun Qian;Zhigang Liu;Xinxin Wang;Xiaobing Zou;Yifan Wang","doi":"10.1109/TPS.2024.3443334","DOIUrl":"https://doi.org/10.1109/TPS.2024.3443334","url":null,"abstract":"An energy-efficient method is developed to generate shock wave (SW) from underwater electrical wire-array explosion. By changing the wire connection of cylindrical wire array, parallel is found usually not the suitable connection of wire array to generate SW at a fixed energy. The suitable connection of wire array is determined by initial energy. At a given initial energy, resistance matching between load and external resistance is an important factor to generate a SW, and the corresponding discharge current is critically damped discharge.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4626-4629"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798024","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3478209
Dongmei Yin;Nan Yu;Chengcheng Sun;Qinghua Lin;Gang Wan
Based on the theory of moving electromagnetic (EM) systems, a 3-D numerical simulation model of the transient EM field of the series-enhanced EM railgun is established by using the finite element (FE)/boundary element (BE) coupling method. The sliding electrical contact between the armature and rails is also considered in this model. The distribution of in-bore magnetic field of this kind of railgun is compared with the one of the monorail railgun. Based on this model, the evolutions of the current of the in-bore shield and the EM field in this shield’s cavity are simulated in its launching process. The effects of the shield’s materials and motion on the induced current and magnetic field of the shield are analyzed. The results reveal that because of the addition of the enhanced rails, the distributions of the current and the magnetic field in the rails and armature for the series-enhanced EM railgun are different from the ones for the monorail railgun, and the distribution of the in-bore magnetic field for the former is more complex than the one for the latter. The structure of induced current in the copper shield is basically similar to the one in the industrial pure iron, but there are some differences in their evolutions between the two kinds of material shields, which lead to the differences in the distributions of the magnetic field. The shield’s motion influences the distribution of the magnetic field in the shield’s cavity, which is a complex process.
{"title":"Numerical Analysis of the In-Bore Magnetic Shielding of the Series-Enhanced Electromagnetic Railgun","authors":"Dongmei Yin;Nan Yu;Chengcheng Sun;Qinghua Lin;Gang Wan","doi":"10.1109/TPS.2024.3478209","DOIUrl":"https://doi.org/10.1109/TPS.2024.3478209","url":null,"abstract":"Based on the theory of moving electromagnetic (EM) systems, a 3-D numerical simulation model of the transient EM field of the series-enhanced EM railgun is established by using the finite element (FE)/boundary element (BE) coupling method. The sliding electrical contact between the armature and rails is also considered in this model. The distribution of in-bore magnetic field of this kind of railgun is compared with the one of the monorail railgun. Based on this model, the evolutions of the current of the in-bore shield and the EM field in this shield’s cavity are simulated in its launching process. The effects of the shield’s materials and motion on the induced current and magnetic field of the shield are analyzed. The results reveal that because of the addition of the enhanced rails, the distributions of the current and the magnetic field in the rails and armature for the series-enhanced EM railgun are different from the ones for the monorail railgun, and the distribution of the in-bore magnetic field for the former is more complex than the one for the latter. The structure of induced current in the copper shield is basically similar to the one in the industrial pure iron, but there are some differences in their evolutions between the two kinds of material shields, which lead to the differences in the distributions of the magnetic field. The shield’s motion influences the distribution of the magnetic field in the shield’s cavity, which is a complex process.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4705-4716"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797919","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3485995
Markus Fischer;Michael Beltle;Stefan Tenbohlen;Dietmar Gentsch;Werner Ebbinghaus
During opening and interruption operations in vacuum chambers, an arc is created during mechanical contact separation, consisting of vaporized contact material. With decreasing current, it becomes an unstable situation, and current can chop before the natural current zero crossing. This transient process, with a high current gradient, can cause high overvoltage in the network, particularly at inductive loads due to resonances. This may result in irreversible damages to the insulation of connected equipment, such as transformers or motors, as well as electromagnetic compatibility (EMC) issues. Switching contact materials for applications in contactors, such as tungsten carbide silver (WC-Ag), show chopping current values ranging from 0.7 to 2.5 A. To reduce chopping currents, different approaches are needed. Specifically, a proper selection of contact materials can minimize chopping currents or, at the very least, shift them closer to the zero crossing. Easily emitting contact materials at low temperatures are favorable. Additional tests cover the superimposition of externally applied magnetic fields during the arc burning phase. This research paper analyzes both the combination of different known and optimized contact materials and the superimposition of axial magnetic fields during interruption operations. Using materials comparable to WC-Ag reduces the chopping current by about 52% without a superimposed magnetic field. Other contact materials show field-dependent characteristics, such as copper chromium (Cu-Cr). Regarding interruption speed, an improvement in chopping behavior is observed with slower movements. Finally, the focus is set on the aging behavior. More than 10 000 switching opening operations are performed in this work, and, with the exception of one material combination, no aging can be observed.
{"title":"Effects of Optimized Switching Contact Materials, Aging, and Superimposed Axial Magnetic Field on Chopping Current in Vacuum Interrupters","authors":"Markus Fischer;Michael Beltle;Stefan Tenbohlen;Dietmar Gentsch;Werner Ebbinghaus","doi":"10.1109/TPS.2024.3485995","DOIUrl":"https://doi.org/10.1109/TPS.2024.3485995","url":null,"abstract":"During opening and interruption operations in vacuum chambers, an arc is created during mechanical contact separation, consisting of vaporized contact material. With decreasing current, it becomes an unstable situation, and current can chop before the natural current zero crossing. This transient process, with a high current gradient, can cause high overvoltage in the network, particularly at inductive loads due to resonances. This may result in irreversible damages to the insulation of connected equipment, such as transformers or motors, as well as electromagnetic compatibility (EMC) issues. Switching contact materials for applications in contactors, such as tungsten carbide silver (WC-Ag), show chopping current values ranging from 0.7 to 2.5 A. To reduce chopping currents, different approaches are needed. Specifically, a proper selection of contact materials can minimize chopping currents or, at the very least, shift them closer to the zero crossing. Easily emitting contact materials at low temperatures are favorable. Additional tests cover the superimposition of externally applied magnetic fields during the arc burning phase. This research paper analyzes both the combination of different known and optimized contact materials and the superimposition of axial magnetic fields during interruption operations. Using materials comparable to WC-Ag reduces the chopping current by about 52% without a superimposed magnetic field. Other contact materials show field-dependent characteristics, such as copper chromium (Cu-Cr). Regarding interruption speed, an improvement in chopping behavior is observed with slower movements. Finally, the focus is set on the aging behavior. More than 10 000 switching opening operations are performed in this work, and, with the exception of one material combination, no aging can be observed.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4419-4427"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797903","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}
Pub Date : 2024-11-07DOI: 10.1109/TPS.2024.3487347
Ziang Tong;Jianwen Wu;Xiwei Jiang;Shengsheng Shi;Shengxiu Wu;Jintao Zhang;Shangwen Xia;Jingyi Lin
Modern aircraft use 360–800 Hz variable-frequency power systems, and the increased frequency makes it more difficult to interrupt the arc. Traditional contacts are difficult to apply due to magnetic hysteresis effects. Curved contacts utilize the curved electrode shape to exhibit advantages in interrupting intermediate-frequency vacuum arcs but lack a design basis for the bending amplitude. This article develops a new type of measurement device for post-arc of intermediate-frequency current and uses it to measure the post-arc of curved contacts with a bending amplitude of 2–4 mm, a diameter of 30 mm, and a contact material of CuCr25. It analyzes the changes in gap conductance under different bending amplitudes and analyzes the mechanism of different bending amplitudes on the post-arc dielectric characteristics of vacuum arcs using a continuous transition model (CTM).
{"title":"Study on Intermediate-Frequency Vacuum Arc Recovery Characteristics of Curved Contact With Different Bending Amplitudes","authors":"Ziang Tong;Jianwen Wu;Xiwei Jiang;Shengsheng Shi;Shengxiu Wu;Jintao Zhang;Shangwen Xia;Jingyi Lin","doi":"10.1109/TPS.2024.3487347","DOIUrl":"https://doi.org/10.1109/TPS.2024.3487347","url":null,"abstract":"Modern aircraft use 360–800 Hz variable-frequency power systems, and the increased frequency makes it more difficult to interrupt the arc. Traditional contacts are difficult to apply due to magnetic hysteresis effects. Curved contacts utilize the curved electrode shape to exhibit advantages in interrupting intermediate-frequency vacuum arcs but lack a design basis for the bending amplitude. This article develops a new type of measurement device for post-arc of intermediate-frequency current and uses it to measure the post-arc of curved contacts with a bending amplitude of 2–4 mm, a diameter of 30 mm, and a contact material of CuCr25. It analyzes the changes in gap conductance under different bending amplitudes and analyzes the mechanism of different bending amplitudes on the post-arc dielectric characteristics of vacuum arcs using a continuous transition model (CTM).","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4506-4513"},"PeriodicalIF":1.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797902","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}
Pub Date : 2024-11-01DOI: 10.1109/TPS.2024.3399467
Peter H. Titus;Han Zhang;J. Fang;A. Brooks;A. Khodak
This article presents the results of transient dynamic simulations of loads due to disruption eddy currents on the NSTXU vacuum vessel. Dynamic loading at diagnostic mounting locations is expressed as response spectra derived from the time history results of the dynamic structural simulations of a variety of disruption scenarios. The disruption simulations draw on a history of the project assessments of worst case disruptions for specific components. Major efforts to assess disruption loading have included the vacuum vessel which is the major structural support for the machine, as well as the passive plates (PPs), high harmonic fast wave (HHFW) antenna, and centerstack casing. Each one of these efforts included transient electromagnetic simulations producing time-dependent eddy current Lorentz loads (and in some cases halo loads) which then were applied to time-dependent structural dynamic analyses intended to obtain the proper dynamic amplification factors. In some instances, the EM model and structural model were identical allowing direct transfer of EM forces to the structural model. In other cases, the EM and structural model were not identical and the vector potential (VP) transfer method was used. The results files from these analyses were available (or re-run) to post process in ANSYS Classic time history postprocessor. The ANSYS command is used to create response spectra from time history data at desired points on the vessel.
{"title":"NSTXU Diagnostic Disruption Dynamic Loading Represented by Response Spectra","authors":"Peter H. Titus;Han Zhang;J. Fang;A. Brooks;A. Khodak","doi":"10.1109/TPS.2024.3399467","DOIUrl":"https://doi.org/10.1109/TPS.2024.3399467","url":null,"abstract":"This article presents the results of transient dynamic simulations of loads due to disruption eddy currents on the NSTXU vacuum vessel. Dynamic loading at diagnostic mounting locations is expressed as response spectra derived from the time history results of the dynamic structural simulations of a variety of disruption scenarios. The disruption simulations draw on a history of the project assessments of worst case disruptions for specific components. Major efforts to assess disruption loading have included the vacuum vessel which is the major structural support for the machine, as well as the passive plates (PPs), high harmonic fast wave (HHFW) antenna, and centerstack casing. Each one of these efforts included transient electromagnetic simulations producing time-dependent eddy current Lorentz loads (and in some cases halo loads) which then were applied to time-dependent structural dynamic analyses intended to obtain the proper dynamic amplification factors. In some instances, the EM model and structural model were identical allowing direct transfer of EM forces to the structural model. In other cases, the EM and structural model were not identical and the vector potential (VP) transfer method was used. The results files from these analyses were available (or re-run) to post process in ANSYS Classic time history postprocessor. The ANSYS command is used to create response spectra from time history data at desired points on the vessel.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"3555-3560"},"PeriodicalIF":1.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810531","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}
This research article presents a high-power radial oscillator in the Ka-band equipped with a radial sheet electron beam. Radial beam devices outperform traditional devices by offering more extensive interaction spaces and reduced space charge effects. This advantage eliminates the necessity for external magnetic fields, efficiently solving the efficiency issues. The design parameters of the presented device for efficient operation in $pi $ mode within the Ka-band frequency spectrum are identified through numerical analysis. The baseline model with a constant period is simulated using particle-in-cell (PIC) solver, and importantly, without an external magnetic field. The simulation features a radial beam cathode with an emission area of $2pi times 107.5times 0.7$ mm, generating a current density of 444.37 A/cm2. At 160- and 170-kV beam voltage, the device achieves efficiencies of 31.05% and 38.5%, with peak powers of 104.3 and 137.8 MW, respectively, while maintaining stable signal frequencies around 34.6 and 34.62 GHz. The baseline model’s performance is further enhanced through various phase-velocity tapering techniques, including linear, exponential, and logarithmic methods. The impact of these velocity tapering approaches on beam-wave interaction is analyzed. Linear tapering, in particular, improves output power to 190.61 MW and efficiency to 53.39%, exceeding the constant period model’s 137.8 MW power and 38.5% efficiency. Although exponential and logarithmic methods also boost efficiency, they are less effective than the linear approach. These tapering techniques lead to minor frequency shifts, indicating their structural influence on the oscillator’s performance.
{"title":"A Ka-Band Radial Beam Oscillator With Phase-Velocity Tapering","authors":"Atif Jameel;Zhanliang Wang;Jibran Latif;Muhammad Khawar Nadeem;Bilawal Ali;Huarong Gong;Qiang Hu;Asif Mehmood Khan;Yubin Gong","doi":"10.1109/TPS.2024.3479722","DOIUrl":"https://doi.org/10.1109/TPS.2024.3479722","url":null,"abstract":"This research article presents a high-power radial oscillator in the Ka-band equipped with a radial sheet electron beam. Radial beam devices outperform traditional devices by offering more extensive interaction spaces and reduced space charge effects. This advantage eliminates the necessity for external magnetic fields, efficiently solving the efficiency issues. The design parameters of the presented device for efficient operation in \u0000<inline-formula> <tex-math>$pi $ </tex-math></inline-formula>\u0000 mode within the Ka-band frequency spectrum are identified through numerical analysis. The baseline model with a constant period is simulated using particle-in-cell (PIC) solver, and importantly, without an external magnetic field. The simulation features a radial beam cathode with an emission area of \u0000<inline-formula> <tex-math>$2pi times 107.5times 0.7$ </tex-math></inline-formula>\u0000 mm, generating a current density of 444.37 A/cm2. At 160- and 170-kV beam voltage, the device achieves efficiencies of 31.05% and 38.5%, with peak powers of 104.3 and 137.8 MW, respectively, while maintaining stable signal frequencies around 34.6 and 34.62 GHz. The baseline model’s performance is further enhanced through various phase-velocity tapering techniques, including linear, exponential, and logarithmic methods. The impact of these velocity tapering approaches on beam-wave interaction is analyzed. Linear tapering, in particular, improves output power to 190.61 MW and efficiency to 53.39%, exceeding the constant period model’s 137.8 MW power and 38.5% efficiency. Although exponential and logarithmic methods also boost efficiency, they are less effective than the linear approach. These tapering techniques lead to minor frequency shifts, indicating their structural influence on the oscillator’s performance.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4544-4552"},"PeriodicalIF":1.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798023","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}
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