Pub Date : 2026-10-01Epub Date: 2026-04-17DOI: 10.1109/TPS.2026.3682552
Ravindra Kumar Sharma;Pratik S. Soni;Vijay Mohale
There have been continuous efforts to reduce self-inductance or equivalent series inductance (ESL) of energy storage capacitors for various high voltage (HV) pulsed power applications. Reduction in self-inductance increases peak discharge current, life, and reduces the voltage reversal and rise of current. This further actually increases the effective use of the stored energy of the pulse capacitor (PC). These pulsed power applications include electromagnetic forming and welding, rail gun, coil gun, plasma device-based neutron and x-ray, high power microwave, exploding wire-based shockwave for oil well and rock fracturing, etc. In this research, similar rating energy storage capacitors for pulsed power applications are designed, developed, and electrically tested for reduction in self-inductance. Four types of stack configuration capacitors with insulating bushings are developed for $8~mu $ F, 4 kV, 8.5 nH in series-connected two capacitor elements; $3.1~mu $ F, 110 kV, 40 nH in horizontal assembly of capacitor elements, and $25~mu $ F, 15 kV, 25 nH in vertical assembly of capacitor elements with six- and eight-packs configurations to demonstrate the reduction in inductance. Position of current path and magnetic flux loop area have also been studied and inferred a major role in the reduction of the self-inductance while incorporating the coaxial insulating bushing and circular conducting terminals. An attempt is put forth to numerically estimate the ESL values, and they are validated with experimental results with good agreement. This article will contain a detailed mathematical estimation methodology of self-inductance for different capacitor configurations and bushings, and will be a good value addition in this HV pulsed power technology. Further, this analytical estimation methodology of ESL is an effective, less time and energy consumption, and economical solution in the development of HV PCs for various pulsed power applications.
{"title":"Analytical Computation and Experimental Validation of Self-Inductance for High-Voltage Pulse Capacitors","authors":"Ravindra Kumar Sharma;Pratik S. Soni;Vijay Mohale","doi":"10.1109/TPS.2026.3682552","DOIUrl":"https://doi.org/10.1109/TPS.2026.3682552","url":null,"abstract":"There have been continuous efforts to reduce self-inductance or equivalent series inductance (ESL) of energy storage capacitors for various high voltage (HV) pulsed power applications. Reduction in self-inductance increases peak discharge current, life, and reduces the voltage reversal and rise of current. This further actually increases the effective use of the stored energy of the pulse capacitor (PC). These pulsed power applications include electromagnetic forming and welding, rail gun, coil gun, plasma device-based neutron and x-ray, high power microwave, exploding wire-based shockwave for oil well and rock fracturing, etc. In this research, similar rating energy storage capacitors for pulsed power applications are designed, developed, and electrically tested for reduction in self-inductance. Four types of stack configuration capacitors with insulating bushings are developed for <inline-formula> <tex-math>$8~mu $ </tex-math></inline-formula>F, 4 kV, 8.5 nH in series-connected two capacitor elements; <inline-formula> <tex-math>$3.1~mu $ </tex-math></inline-formula>F, 110 kV, 40 nH in horizontal assembly of capacitor elements, and <inline-formula> <tex-math>$25~mu $ </tex-math></inline-formula>F, 15 kV, 25 nH in vertical assembly of capacitor elements with six- and eight-packs configurations to demonstrate the reduction in inductance. Position of current path and magnetic flux loop area have also been studied and inferred a major role in the reduction of the self-inductance while incorporating the coaxial insulating bushing and circular conducting terminals. An attempt is put forth to numerically estimate the ESL values, and they are validated with experimental results with good agreement. This article will contain a detailed mathematical estimation methodology of self-inductance for different capacitor configurations and bushings, and will be a good value addition in this HV pulsed power technology. Further, this analytical estimation methodology of ESL is an effective, less time and energy consumption, and economical solution in the development of HV PCs for various pulsed power applications.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5410-5417"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149175978","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}
The design, manufacturing, and experimental characterization of the prototype of an electron cyclotron heating (ECH) mirror equipped with an innovative cooling system based on triply periodic minimal surfaces (TPMS) is presented here. The prototype, manufactured in AISI 316L via selective laser melting (SLM), is engineered to withstand high heat fluxes and to mitigate eddy currents induced during tokamak operation. The TPMS cooling structure features a Gyroid topology with variable cell size. Hydraulic and thermal tests were conducted in a dedicated water loop, and experimental results were compared to numerical predictions. The measured pressure drops were worse than those calculated, probably due to surface roughness and geometrical deviations, and can be reproduced numerically with a geometry with an effective porosity lower than the nominal one. The thermal measurements, on the other hand, appear to be quite far from the simulations, probably due to the influence of the experimental setup on the thermocouple readings. These findings confirm the potential of TPMS-based cooling for ECH mirrors and highlight areas for further improvement in manufacturing, modeling, and testing.
{"title":"Design, Manufacturing, and Experimental Characterization of a First-of-a-Kind DTT ECH Mirror Equipped With TPMS","authors":"Eleonora Gajetti;Alessandro Bruschi;Francesco Fanale;William Ferretto;Gustavo Granucci;Andrea Lucchini;Luca Marocco;Afra Romano;Laura Savoldi","doi":"10.1109/TPS.2026.3700964","DOIUrl":"https://doi.org/10.1109/TPS.2026.3700964","url":null,"abstract":"The design, manufacturing, and experimental characterization of the prototype of an electron cyclotron heating (ECH) mirror equipped with an innovative cooling system based on triply periodic minimal surfaces (TPMS) is presented here. The prototype, manufactured in AISI 316L via selective laser melting (SLM), is engineered to withstand high heat fluxes and to mitigate eddy currents induced during tokamak operation. The TPMS cooling structure features a Gyroid topology with variable cell size. Hydraulic and thermal tests were conducted in a dedicated water loop, and experimental results were compared to numerical predictions. The measured pressure drops were worse than those calculated, probably due to surface roughness and geometrical deviations, and can be reproduced numerically with a geometry with an effective porosity lower than the nominal one. The thermal measurements, on the other hand, appear to be quite far from the simulations, probably due to the influence of the experimental setup on the thermocouple readings. These findings confirm the potential of TPMS-based cooling for ECH mirrors and highlight areas for further improvement in manufacturing, modeling, and testing.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5503-5510"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11570246","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149175987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-01Epub Date: 2026-03-22DOI: 10.1109/TPS.2026.3693042
Manuel Nierenberg;Myriam Koch;Michael Kurrat
This study investigates the direct current (DC) interruption behavior and arc dynamics of three vacuum interrupter (VI) contact geometries: butt, axial magnetic field (AMF), and transverse magnetic field. Arcing voltage, current shape, and high-speed optical diagnostics are used for the comparison. Experimental results reveal significant differences in arc development, arc motion, and interruption performance. High-speed imaging shows distinct arc transport mechanisms for each contact type, which are correlated with interruption capability and dynamic behavior near current zero. This research shows that magnetic arc control is even more important when switching DC. Fast switching times result in weakly rotating arc features for transversal magnetic field contacts but well-developed cathode spot distribution for axial magnetic field contacts. The findings provide insights into considerations when designing special contact geometries for DC vacuum technology.
{"title":"DC Interruption and Arc Dynamics of Butt, AMF, and TMF Contact Systems in Vacuum Interrupters","authors":"Manuel Nierenberg;Myriam Koch;Michael Kurrat","doi":"10.1109/TPS.2026.3693042","DOIUrl":"https://doi.org/10.1109/TPS.2026.3693042","url":null,"abstract":"This study investigates the direct current (DC) interruption behavior and arc dynamics of three vacuum interrupter (VI) contact geometries: butt, axial magnetic field (AMF), and transverse magnetic field. Arcing voltage, current shape, and high-speed optical diagnostics are used for the comparison. Experimental results reveal significant differences in arc development, arc motion, and interruption performance. High-speed imaging shows distinct arc transport mechanisms for each contact type, which are correlated with interruption capability and dynamic behavior near current zero. This research shows that magnetic arc control is even more important when switching DC. Fast switching times result in weakly rotating arc features for transversal magnetic field contacts but well-developed cathode spot distribution for axial magnetic field contacts. The findings provide insights into considerations when designing special contact geometries for DC vacuum technology.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"4936-4943"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176106","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}
Mutual interference and high overmoded ratios in multiband frequency-agile high-power microwave (FA-HPM) oscillators readily induce asymmetric mode competition, severely degrading the output power and pulsewidth in experiments. Traditional asymmetric mode competition suppression methods are designed for single-frequency HPM oscillators, making them inadequate for ensuring operating stability across multiple frequencies in FA-HPM oscillators and prone to introducing new asymmetric mode competition. To address this challenge, this article proposes a novel asymmetric mode competition suppression method for multiband FA-HPM oscillators. This method relies on a “locate-analyze-optimize” mechanism to suppress the asymmetric mode competition induced by the TM112 and TM212 modes under Ku-band operation, as well as the EH31 mode under X-band operation in the triple-band FA-HPM oscillator. It identifies the excitation region of asymmetric modes through temporal evolution analysis of the electron beam’s kinetic energy, revealing that a high external quality factor ($Q_{e}$ ) and high reflection characteristics are the key factors contributing to the excitation and growth of asymmetric modes. Ultimately, the excitation of asymmetric modes is effectively suppressed by increasing the gap width of the high-frequency structures. Under actual voltage waveform conditions, no asymmetric mode competition occurs in this device. In addition, this method can be applied to resolve asymmetric mode competition issues in various O-type high-power microwave oscillators.
{"title":"Asymmetric Mode Competition Excitation and Suppression in a Triple-Band Frequency-Agile High-Power Microwave Oscillator","authors":"Xingjun Ge;Xiaodong Hu;Hang Chi;Rujin Deng;Peng Zhang;Tao Li;Baoliang Qian","doi":"10.1109/TPS.2026.3732506","DOIUrl":"https://doi.org/10.1109/TPS.2026.3732506","url":null,"abstract":"Mutual interference and high overmoded ratios in multiband frequency-agile high-power microwave (FA-HPM) oscillators readily induce asymmetric mode competition, severely degrading the output power and pulsewidth in experiments. Traditional asymmetric mode competition suppression methods are designed for single-frequency HPM oscillators, making them inadequate for ensuring operating stability across multiple frequencies in FA-HPM oscillators and prone to introducing new asymmetric mode competition. To address this challenge, this article proposes a novel asymmetric mode competition suppression method for multiband FA-HPM oscillators. This method relies on a “locate-analyze-optimize” mechanism to suppress the asymmetric mode competition induced by the TM<sub>112</sub> and TM<sub>212</sub> modes under Ku-band operation, as well as the EH<sub>31</sub> mode under X-band operation in the triple-band FA-HPM oscillator. It identifies the excitation region of asymmetric modes through temporal evolution analysis of the electron beam’s kinetic energy, revealing that a high external quality factor (<inline-formula> <tex-math>$Q_{e}$ </tex-math></inline-formula>) and high reflection characteristics are the key factors contributing to the excitation and growth of asymmetric modes. Ultimately, the excitation of asymmetric modes is effectively suppressed by increasing the gap width of the high-frequency structures. Under actual voltage waveform conditions, no asymmetric mode competition occurs in this device. In addition, this method can be applied to resolve asymmetric mode competition issues in various O-type high-power microwave oscillators.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5077-5085"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176138","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 : 2026-10-01Epub Date: 2026-09-10DOI: 10.1109/TPS.2026.3729772
Rajneet Kaur;S. Sihotra;N. S. Saini
In this study, we investigate the propagation characteristics of electron-acoustic (EA) breather structures in an unmagnetized plasma consisting of cold electrons as a fluid, an electron beam, nonthermal hot electrons, and stationary ions. Using the multiple-scale perturbation method, the nonlinear Schrödinger equation nonlinear Schrodinger equation (NLSE) is derived. Exact solutions of the NLSE yield various breather-type nonlinear structures. The effects of an electron beam, the nonthermal parameter of hot electrons, and other plasma parameters on the amplitude, width, and localization properties of breather structures are analyzed. The findings of this investigation may be of great importance for understanding the dynamics of EA nonlinear structures in astrophysical/space plasmas.
{"title":"Electrostatic Breather Structures in an Electron Beam Plasma With Nonthermal Hot Electrons","authors":"Rajneet Kaur;S. Sihotra;N. S. Saini","doi":"10.1109/TPS.2026.3729772","DOIUrl":"https://doi.org/10.1109/TPS.2026.3729772","url":null,"abstract":"In this study, we investigate the propagation characteristics of electron-acoustic (EA) breather structures in an unmagnetized plasma consisting of cold electrons as a fluid, an electron beam, nonthermal hot electrons, and stationary ions. Using the multiple-scale perturbation method, the nonlinear Schrödinger equation nonlinear Schrodinger equation (NLSE) is derived. Exact solutions of the NLSE yield various breather-type nonlinear structures. The effects of an electron beam, the nonthermal parameter of hot electrons, and other plasma parameters on the amplitude, width, and localization properties of breather structures are analyzed. The findings of this investigation may be of great importance for understanding the dynamics of EA nonlinear structures in astrophysical/space plasmas.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5583-5589"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176160","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 : 2026-10-01Epub Date: 2026-07-29DOI: 10.1109/TPS.2026.3714043
Francesco Santoro;Alberto Ferro;Alberto Maistrello;Elena Gaio;Bhavana Gudala;Matteo Civale
The magnetic energy storage and transfer (MEST) system is a technology conceived to address the issues of high active power transients and huge reactive power demand of conventional coil power supplies (CPSs), thus providing an effective solution to be employed in future large fusion reactors. The MEST system exploits an additional superconducting coil sink coil (KC) as an energy storage to sustain the operation of the load coil (LC). Through a switching section and a capacitor bank, it is able to transfer energy bidirectionally between the two superconducting coils, to provide the required current to the LC. Thanks to this storage, the external AC grid must supply only the average power through a power supply (PS) that charges the KC. A small-scale prototype of the MEST system is nearing completion, serving as a proof of concept and enabling the investigation of scaling the design to higher power ratings. The prototype operates with a resistive sink and LCs and follows a modular approach for the switching section (combined with the capacitor bank), with two modules in total. The modules are designed for operation at 2 kV and 2 kA and can function independently or be connected to achieve higher ratings. This prototype will permit the evaluation of the advantages and limitations of the specific topology, examine various configurations, test different control strategies, and understand any unexpected experimental findings. The first tests focus on verifying the prototype’s functionality, particularly the integration of the components, and assessing the system’s ability to effectively control the currents in both coils. This work presents the results of the initial tests, the first characterization of the circuit, and the validation of the developed numerical models with experimental data.
{"title":"First Experimental Characterization of the Magnetic Energy Storage and Transfer (MEST) System","authors":"Francesco Santoro;Alberto Ferro;Alberto Maistrello;Elena Gaio;Bhavana Gudala;Matteo Civale","doi":"10.1109/TPS.2026.3714043","DOIUrl":"https://doi.org/10.1109/TPS.2026.3714043","url":null,"abstract":"The magnetic energy storage and transfer (MEST) system is a technology conceived to address the issues of high active power transients and huge reactive power demand of conventional coil power supplies (CPSs), thus providing an effective solution to be employed in future large fusion reactors. The MEST system exploits an additional superconducting coil sink coil (KC) as an energy storage to sustain the operation of the load coil (LC). Through a switching section and a capacitor bank, it is able to transfer energy bidirectionally between the two superconducting coils, to provide the required current to the LC. Thanks to this storage, the external AC grid must supply only the average power through a power supply (PS) that charges the KC. A small-scale prototype of the MEST system is nearing completion, serving as a proof of concept and enabling the investigation of scaling the design to higher power ratings. The prototype operates with a resistive sink and LCs and follows a modular approach for the switching section (combined with the capacitor bank), with two modules in total. The modules are designed for operation at 2 kV and 2 kA and can function independently or be connected to achieve higher ratings. This prototype will permit the evaluation of the advantages and limitations of the specific topology, examine various configurations, test different control strategies, and understand any unexpected experimental findings. The first tests focus on verifying the prototype’s functionality, particularly the integration of the components, and assessing the system’s ability to effectively control the currents in both coils. This work presents the results of the initial tests, the first characterization of the circuit, and the validation of the developed numerical models with experimental data.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5545-5550"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176218","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 : 2026-10-01Epub Date: 2026-09-21DOI: 10.1109/TPS.2026.3730029
Ram Prakash;Vinit Kumar
We present a self-consistent analysis of the cavity voltage evolution in elliptic superconducting radio frequency (SRF) cavities under RF excitation in the presence of multipacting (MP), accounting for the dynamic RF loading induced by the evolving MP current. A previously proposed model for the parallel-plate geometry, based on an equivalent parallel LCR circuit and a current source representing the MP current, is suitably generalized to elliptic SRF cavities, where, unlike in the parallel-plate case, the MP electrons may follow trajectories distinct from those of the beam particles. Computations performed using this model explicitly show that when the cavity gets trapped in an MP state, the cavity voltage initially exhibits rapid oscillations before stabilizing just above the lower threshold of the MP barrier. It is demonstrated that in some cases, applying sufficiently high forward RF power can overcome the MP barrier entirely, allowing stable operation. The effect of mutual repulsion between MP electrons and also of image charges on the conducting surface is also included in the analysis with certain approximations, and its impact on cavity voltage evolution is analyzed—especially in the context of overcoming the MP barrier. A parameter $eta $ , representing the reduction in the MP growth rate due to cavity surface conditioning, is introduced, and the cavity voltage evolution is computed for different input powers and $eta $ to identify the parameter space in which the MP barrier can be completely overcome, enabling stable operation above its upper threshold.
{"title":"Phenomenological Study of the RF Loading Effects Due to Multipacting Current in the Elliptic SRF Cavities","authors":"Ram Prakash;Vinit Kumar","doi":"10.1109/TPS.2026.3730029","DOIUrl":"https://doi.org/10.1109/TPS.2026.3730029","url":null,"abstract":"We present a self-consistent analysis of the cavity voltage evolution in elliptic superconducting radio frequency (SRF) cavities under RF excitation in the presence of multipacting (MP), accounting for the dynamic RF loading induced by the evolving MP current. A previously proposed model for the parallel-plate geometry, based on an equivalent parallel <italic>LCR</i> circuit and a current source representing the MP current, is suitably generalized to elliptic SRF cavities, where, unlike in the parallel-plate case, the MP electrons may follow trajectories distinct from those of the beam particles. Computations performed using this model explicitly show that when the cavity gets trapped in an MP state, the cavity voltage initially exhibits rapid oscillations before stabilizing just above the lower threshold of the MP barrier. It is demonstrated that in some cases, applying sufficiently high forward RF power can overcome the MP barrier entirely, allowing stable operation. The effect of mutual repulsion between MP electrons and also of image charges on the conducting surface is also included in the analysis with certain approximations, and its impact on cavity voltage evolution is analyzed—especially in the context of overcoming the MP barrier. A parameter <inline-formula> <tex-math>$eta $ </tex-math></inline-formula>, representing the reduction in the MP growth rate due to cavity surface conditioning, is introduced, and the cavity voltage evolution is computed for different input powers and <inline-formula> <tex-math>$eta $ </tex-math></inline-formula> to identify the parameter space in which the MP barrier can be completely overcome, enabling stable operation above its upper threshold.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5058-5068"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176287","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}
During the breaking process of vacuum circuit breakers, the arc will cause the anode to heat up and melt. This will have a negative impact on the circuit breaker and reduce its life. In this study, a 3-D transient model is established to simulate the interaction between arc and anode. The process of electrode melting under arc heating and electrode evaporation affecting the arc is considered. In this study, an axial magnetic field (AMF) contact made of copper-chromium alloy with a diameter of 41 mm was used. The gap distance is 10 mm and the current has a root mean square (rms) value of 15 kA. This study takes CuCr30 material as the main research object. The simulation results show that the CuCr30 electrode is heated up under the action of the arc and reaches the maximum value at 6.6 ms, accompanied by an erosion depth of about $120~mu $ m. Moreover, the overall erosion region exhibits a hexagonal distribution under the influence of the arc plasma. The comparison between CuCr10, CuCr30, and CuCr50 material electrodes shows that the higher the chromium content, the higher the anode temperature, but the lower the degree of erosion. The temperature rise of the electrode also affected the arc column, leading to an active anode phenomenon. Overall, the phenomena observed in the simulation are in good agreement with the experimental observations.
{"title":"3-D Transient Modeling and Simulation of Coupled Vacuum Arc and Anode Molten Pool Deformation Under CuCr Alloy Contacts","authors":"Jieli Chen;Lijun Wang;Xiangyu Wang;Hongjian Wang;Yiduo Xie;Zhefeng Zhang","doi":"10.1109/TPS.2026.3695594","DOIUrl":"https://doi.org/10.1109/TPS.2026.3695594","url":null,"abstract":"During the breaking process of vacuum circuit breakers, the arc will cause the anode to heat up and melt. This will have a negative impact on the circuit breaker and reduce its life. In this study, a 3-D transient model is established to simulate the interaction between arc and anode. The process of electrode melting under arc heating and electrode evaporation affecting the arc is considered. In this study, an axial magnetic field (AMF) contact made of copper-chromium alloy with a diameter of 41 mm was used. The gap distance is 10 mm and the current has a root mean square (rms) value of 15 kA. This study takes CuCr30 material as the main research object. The simulation results show that the CuCr30 electrode is heated up under the action of the arc and reaches the maximum value at 6.6 ms, accompanied by an erosion depth of about <inline-formula> <tex-math>$120~mu $ </tex-math></inline-formula>m. Moreover, the overall erosion region exhibits a hexagonal distribution under the influence of the arc plasma. The comparison between CuCr10, CuCr30, and CuCr50 material electrodes shows that the higher the chromium content, the higher the anode temperature, but the lower the degree of erosion. The temperature rise of the electrode also affected the arc column, leading to an active anode phenomenon. Overall, the phenomena observed in the simulation are in good agreement with the experimental observations.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"4748-4757"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11538321","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-10-01Epub Date: 2026-09-07DOI: 10.1109/TPS.2026.3728421
Chao Qian;Ruidi Liu;Kunxiang Chen;Kun Yao;Hainan Liu
A coupled particle-in-cell and volume-of-fluid (PIC–VOF) framework is developed to simulate plasma–droplet interactions under a DC negative-corona discharge. The plasma is described by an electrostatic PIC model with Monte Carlo collisions that track electrons, N${}_{2}^{+}$ , O${}_{2}^{+}$ , and O${}_{2}^{-}$ , resolving the negative-ion space charge that dominates the drift region self-consistently. The droplet is treated as a leaky-dielectric incompressible fluid governed by the Navier–Stokes equations with VOF interface tracking, a wall contact-angle boundary condition, and a Navier-slip moving-contact-line model; interfacial absorption of charged particles updates the droplet free charge self-consistently. The electric body force is the Korteweg–Helmholtz density, including Coulomb and dielectrophoretic (DEP) contributions, verified against a Maxwell stress control-surface integral within 3%. A multiscale coupling scheme with incremental PIC re-convergence renders the 360-ms transport simulation tractable. The computed corona current of $23~{mu }$ A and the Warburg-type plate current profile (exponent ${n}=4.8pm 0.3$ ) agree with the experiment of Li et al. within 5%, and the simulated droplet positions at five instants and the peak velocity of 0.061 m/s reproduce the measurements within the experimental reading uncertainty. Force decomposition shows that the DEP force dominates the transport, acting as a restoring force that reverses sign near the maxima of ${E}^{2}$ beneath the blade edges, while the Coulomb force is two to three orders of magnitude smaller because leaky-dielectric relaxation drains the deposited charge to the grounded substrate on a microsecond time scale, holding the droplet charge three to four orders of magnitude below the Pauthenier saturation limit. Sensitivity and control runs identify leaky-dielectric drainage as the controlling mechanism, and the uncertainty of the 2-D approximation is quantified at ±30%–50%.
建立了一个耦合的细胞内粒子和流体体积（PIC-VOF）框架来模拟直流负电晕放电下等离子体-液滴的相互作用。用蒙特卡罗碰撞的静电PIC模型描述等离子体，该模型跟踪电子N ${}_{2}^{+}$, O ${}_{2}^{+}$和O ${}_{2}^{-}$，自洽地解析了主导漂移区的负离子空间电荷。采用具有VOF界面跟踪的Navier-Stokes方程、壁面接触角边界条件和navier -滑移移动接触线模型，将液滴视为漏介不可压缩流体；带电粒子的界面吸收自一致地更新液滴的自由电荷。电体力是Korteweg-Helmholtz密度，包括库仑和介电泳（DEP）贡献，根据麦克斯韦应力控制面积分在3%以内进行验证。一种具有增量PIC再收敛的多尺度耦合方案使得360毫秒传输仿真易于处理。计算得到的电晕电流$23~{mu}$ A和warburg型平板电流曲线（指数${n}=4.8pm 0.3$）与Li等人的实验结果吻合在5%以内，模拟的液滴在5个瞬间的位置和峰值速度0.061 m/s与实验读数不确定度范围内的测量结果吻合。力分解表明，DEP力主导了输运，作为一种恢复力，在叶片边缘附近的最大值${E}^{2}$附近反转符号，而库仑力要小2到3个数量级，因为漏电介质弛豫在微秒时间尺度上将沉积的电荷排到接的基片上，使液滴电荷低于Pauthenier饱和极限3到4个数量级。灵敏度和控制运行确定介质漏泄为控制机制，二维近似的不确定度量化为±30%-50%。
{"title":"Numerical Simulation of Plasma--Droplet Interactions Under an Electric Field","authors":"Chao Qian;Ruidi Liu;Kunxiang Chen;Kun Yao;Hainan Liu","doi":"10.1109/TPS.2026.3728421","DOIUrl":"https://doi.org/10.1109/TPS.2026.3728421","url":null,"abstract":"A coupled particle-in-cell and volume-of-fluid (PIC–VOF) framework is developed to simulate plasma–droplet interactions under a DC negative-corona discharge. The plasma is described by an electrostatic PIC model with Monte Carlo collisions that track electrons, N<inline-formula> <tex-math>${}_{2}^{+}$ </tex-math></inline-formula>, O<inline-formula> <tex-math>${}_{2}^{+}$ </tex-math></inline-formula>, and O<inline-formula> <tex-math>${}_{2}^{-}$ </tex-math></inline-formula>, resolving the negative-ion space charge that dominates the drift region self-consistently. The droplet is treated as a leaky-dielectric incompressible fluid governed by the Navier–Stokes equations with VOF interface tracking, a wall contact-angle boundary condition, and a Navier-slip moving-contact-line model; interfacial absorption of charged particles updates the droplet free charge self-consistently. The electric body force is the Korteweg–Helmholtz density, including Coulomb and dielectrophoretic (DEP) contributions, verified against a Maxwell stress control-surface integral within 3%. A multiscale coupling scheme with incremental PIC re-convergence renders the 360-ms transport simulation tractable. The computed corona current of <inline-formula> <tex-math>$23~{mu }$ </tex-math></inline-formula>A and the Warburg-type plate current profile (exponent <inline-formula> <tex-math>${n}=4.8pm 0.3$ </tex-math></inline-formula>) agree with the experiment of Li et al. within 5%, and the simulated droplet positions at five instants and the peak velocity of 0.061 m/s reproduce the measurements within the experimental reading uncertainty. Force decomposition shows that the DEP force dominates the transport, acting as a restoring force that reverses sign near the maxima of <inline-formula> <tex-math>${E}^{2}$ </tex-math></inline-formula> beneath the blade edges, while the Coulomb force is two to three orders of magnitude smaller because leaky-dielectric relaxation drains the deposited charge to the grounded substrate on a microsecond time scale, holding the droplet charge three to four orders of magnitude below the Pauthenier saturation limit. Sensitivity and control runs identify leaky-dielectric drainage as the controlling mechanism, and the uncertainty of the 2-D approximation is quantified at ±30%–50%.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5256-5272"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176296","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 : 2026-10-01Epub Date: 2026-09-17DOI: 10.1109/TPS.2026.3732861
N. Praveena;M. Vijaya Kumar;M. Sumathy;S. K. Datta
A design and analysis of a corrugated cylindrical waveguide (CCWG) have been carried out for RF parameters such as dispersion and interaction impedance characteristics in the present work. The analysis is carried out for the axisymmetric fundamental TM01-mode and higher order TM02-mode using an analytical approach and benchmarked against 3-D electromagnetic analysis. A typical structure has been designed at X-band, fabricated, and cold-test measurements are carried out to measure the dispersion characteristics. The measured results are compared against analytical and simulated results, which show close agreement. Using the RF parameters, the growth rate of the structure has been computed for the operating voltage of 350 kV and beam current of 4 kA, to study the merits of higher order TM02-mode against fundamental TM01-mode for high-power microwave devices. The efficacy of the structure, which operates in TM02-mode in a dual-beam configuration, is brought out.
{"title":"Design and Analysis of Corrugated Cylindrical Waveguide for HPM Application","authors":"N. Praveena;M. Vijaya Kumar;M. Sumathy;S. K. Datta","doi":"10.1109/TPS.2026.3732861","DOIUrl":"https://doi.org/10.1109/TPS.2026.3732861","url":null,"abstract":"A design and analysis of a corrugated cylindrical waveguide (CCWG) have been carried out for RF parameters such as dispersion and interaction impedance characteristics in the present work. The analysis is carried out for the axisymmetric fundamental TM<sub>01</sub>-mode and higher order TM<sub>02</sub>-mode using an analytical approach and benchmarked against 3-D electromagnetic analysis. A typical structure has been designed at X-band, fabricated, and cold-test measurements are carried out to measure the dispersion characteristics. The measured results are compared against analytical and simulated results, which show close agreement. Using the RF parameters, the growth rate of the structure has been computed for the operating voltage of 350 kV and beam current of 4 kA, to study the merits of higher order TM<sub>02</sub>-mode against fundamental TM<sub>01</sub>-mode for high-power microwave devices. The efficacy of the structure, which operates in TM<sub>02</sub>-mode in a dual-beam configuration, is brought out.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"54 10","pages":"5051-5057"},"PeriodicalIF":1.6,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149175966","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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