A Fluent-based simulation model was established to explore the anode current density distribution, as well as the internal temperature and velocity fields with three typical anode structures: cylindrical type, Laval type, and constricted type. First, by analyzing the relevant governing equations and theories of the laminar plasma torch, a numerical simulation model based on Fluent was developed, and its validity was verified through experiments. Then, using the constructed model, the temperature and velocity fields within the plasma torch, along with the anode surface current density distribution, were simulated and analyzed. Finally, based on a comparative analysis of the simulation results, optimization suggestions for the anode structure were proposed. The results indicate that: 1) the error between the simulation results and the experimental results of the constructed simulation model is less than 3%; 2) cylindrical-type anode current density > constricted-type anode current density > Laval-type anode current density; 3) the three typical anode structures have little influence on the temperature field within the plasma torch; however, in the anode outlet area, the outlet center temperature of the cylindrical-type anode structure is the lowest, and the radial temperature gradient is the largest; and the outlet central temperature of the Laval-type structure is slightly lower than that of the constricted-type structure, but its radial temperature gradient is the smallest, which is conducive to the uniform dispersion of the plasma flow temperature; and 4) the velocity field corresponding to the cylindrical-type structure is slightly lower than that corresponding to the Laval-type structure and the constricted-type structure. Moreover, when the Laval-type structure is adopted, the velocity in the anode area is only slightly lower than that of the constricted structure.
{"title":"Effects of Anode Structures on the Laminar Plasma Jet Characteristics Based on Fluent Simulation Method","authors":"Xiuquan Cao;Ling Luo;Yong He;Xing Liu;Yi Zhao;Yufeng Tang","doi":"10.1109/TPS.2025.3598054","DOIUrl":"https://doi.org/10.1109/TPS.2025.3598054","url":null,"abstract":"A Fluent-based simulation model was established to explore the anode current density distribution, as well as the internal temperature and velocity fields with three typical anode structures: cylindrical type, Laval type, and constricted type. First, by analyzing the relevant governing equations and theories of the laminar plasma torch, a numerical simulation model based on Fluent was developed, and its validity was verified through experiments. Then, using the constructed model, the temperature and velocity fields within the plasma torch, along with the anode surface current density distribution, were simulated and analyzed. Finally, based on a comparative analysis of the simulation results, optimization suggestions for the anode structure were proposed. The results indicate that: 1) the error between the simulation results and the experimental results of the constructed simulation model is less than 3%; 2) cylindrical-type anode current density > constricted-type anode current density > Laval-type anode current density; 3) the three typical anode structures have little influence on the temperature field within the plasma torch; however, in the anode outlet area, the outlet center temperature of the cylindrical-type anode structure is the lowest, and the radial temperature gradient is the largest; and the outlet central temperature of the Laval-type structure is slightly lower than that of the constricted-type structure, but its radial temperature gradient is the smallest, which is conducive to the uniform dispersion of the plasma flow temperature; and 4) the velocity field corresponding to the cylindrical-type structure is slightly lower than that corresponding to the Laval-type structure and the constricted-type structure. Moreover, when the Laval-type structure is adopted, the velocity in the anode area is only slightly lower than that of the constricted structure.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 10","pages":"3144-3152"},"PeriodicalIF":1.5,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290266","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 : 2025-08-22DOI: 10.1109/TPS.2025.3598042
G. Y. Pan;J. C. Cai;Z. X. Su;X. K. Zhang;Z. Zhang;Z. X. Liang;M. Asad;C. Zhang;L. Zeng;X. C. Lin;P. C. Yin;J. Xu;L. N. Yue;H. R. Yin;Y. Xu;G. Q. Zhao;W. X. Wang;Y. Y. Wei
To realize the miniaturization of RF sources for applications in dynamic nuclear polarization–nuclear magnetic resonance (DNP–NMR) spectroscopy, a compact continuous-wave (CW) 263-GHz extended interaction klystron (EIK) frequency upconverter is designed and proposed in this article, including the high-frequency circuit and a complete compact beam optical system (BOS) based on hybrid permanent magnets. This G-band EIK could be driven by easily accessible W-band signal with power level less than 1 W. A local magnetic field enhancement technology is used in the BOS to allow the beam to be further compressed in the tiny drifting tunnel of output cavity, achieving full cylindrical-beam transmission along the whole hybrid circuit. Particle-in-cell (PIC) simulation results show that the saturated output power of the designed EIK could reach over 250 W at 263 GHz, with an operating beam voltage of 24 kV and a beam current of 0.3 A. In addition, its instantaneous bandwidth is broad enough to meet the requirements of DNP–NMR power source where no instability is observed. The key specifications demonstrate that the designed EIK could stably operate in CW mode. This study is expected to provide new approach for the design of cost-efficient sub-THz EIKs in a compact profile, aiming for DNP–NMR applications and beyond.
{"title":"Demonstration of a Compact CW 263-GHz Extended Interaction Klystron Frequency Upconverter","authors":"G. Y. Pan;J. C. Cai;Z. X. Su;X. K. Zhang;Z. Zhang;Z. X. Liang;M. Asad;C. Zhang;L. Zeng;X. C. Lin;P. C. Yin;J. Xu;L. N. Yue;H. R. Yin;Y. Xu;G. Q. Zhao;W. X. Wang;Y. Y. Wei","doi":"10.1109/TPS.2025.3598042","DOIUrl":"https://doi.org/10.1109/TPS.2025.3598042","url":null,"abstract":"To realize the miniaturization of RF sources for applications in dynamic nuclear polarization–nuclear magnetic resonance (DNP–NMR) spectroscopy, a compact continuous-wave (CW) 263-GHz extended interaction klystron (EIK) frequency upconverter is designed and proposed in this article, including the high-frequency circuit and a complete compact beam optical system (BOS) based on hybrid permanent magnets. This G-band EIK could be driven by easily accessible W-band signal with power level less than 1 W. A local magnetic field enhancement technology is used in the BOS to allow the beam to be further compressed in the tiny drifting tunnel of output cavity, achieving full cylindrical-beam transmission along the whole hybrid circuit. Particle-in-cell (PIC) simulation results show that the saturated output power of the designed EIK could reach over 250 W at 263 GHz, with an operating beam voltage of 24 kV and a beam current of 0.3 A. In addition, its instantaneous bandwidth is broad enough to meet the requirements of DNP–NMR power source where no instability is observed. The key specifications demonstrate that the designed EIK could stably operate in CW mode. This study is expected to provide new approach for the design of cost-efficient sub-THz EIKs in a compact profile, aiming for DNP–NMR applications and beyond.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2219-2225"},"PeriodicalIF":1.5,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073428","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 : 2025-08-22DOI: 10.1109/TPS.2025.3589221
Bin Zhang;Changlin Zou;Shuqun Wu
This study develops a zero-dimensional kinetic model to investigate the effects of nanosecond pulsed discharge on the ignition characteristics of stoichiometric ethylene–air mixtures. The simulation framework combines ZDPlasKin for plasma kinetics and CHEMKIN for combustion chemistry. At an initial temperature of 1200 K, a pressure of 1.1 atm, and a fixed plasma energy input of 20 mJ/cm3, the results show that the nanosecond discharge significantly shortens the ignition delay time compared to autoignition. The ignition enhancement strongly depends on the reduced electric field $E/N$ , reaching a minimum delay at 200 Td. The primary radicals responsible for promoting ignition—O, H, C2H, and C2H3—are mainly produced through quenching reactions of electronically excited nitrogen species, particularly N2(A) and N2($text{a}^{prime }$ ). Path flux analysis reveals that electron collisions contribute significantly to O formation, while H and C2H3 are predominantly formed via N2 quenching. The variation in radical production with $E/N$ explains the non monotonic trend of ignition delay time.
{"title":"Kinetic Effects of Nanosecond Discharge on the Ignition Delay of Ethylene–Air Mixtures","authors":"Bin Zhang;Changlin Zou;Shuqun Wu","doi":"10.1109/TPS.2025.3589221","DOIUrl":"https://doi.org/10.1109/TPS.2025.3589221","url":null,"abstract":"This study develops a zero-dimensional kinetic model to investigate the effects of nanosecond pulsed discharge on the ignition characteristics of stoichiometric ethylene–air mixtures. The simulation framework combines ZDPlasKin for plasma kinetics and CHEMKIN for combustion chemistry. At an initial temperature of 1200 K, a pressure of 1.1 atm, and a fixed plasma energy input of 20 mJ/cm<sup>3</sup>, the results show that the nanosecond discharge significantly shortens the ignition delay time compared to autoignition. The ignition enhancement strongly depends on the reduced electric field <inline-formula> <tex-math>$E/N$ </tex-math></inline-formula>, reaching a minimum delay at 200 Td. The primary radicals responsible for promoting ignition—O, H, C<sub>2</sub>H, and C<sub>2</sub>H<sub>3</sub>—are mainly produced through quenching reactions of electronically excited nitrogen species, particularly N<sub>2</sub>(A) and N<sub>2</sub>(<inline-formula> <tex-math>$text{a}^{prime }$ </tex-math></inline-formula>). Path flux analysis reveals that electron collisions contribute significantly to O formation, while H and C<sub>2</sub>H<sub>3</sub> are predominantly formed via N<sub>2</sub> quenching. The variation in radical production with <inline-formula> <tex-math>$E/N$ </tex-math></inline-formula> explains the non monotonic trend of ignition delay time.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2161-2167"},"PeriodicalIF":1.5,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073187","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 : 2025-08-22DOI: 10.1109/TPS.2025.3597884
M. Noorul Haque;K. Sunitha
Assessing the dielectric withstand strength of every equipment in a power system is crucial for insulation coordination. The flashover voltage (FOV) of polymeric insulators due to a lightning impulse (LI) is computed by modeling the air discharge using air plasma chemistry and the movement of the charged species using the charge transport model. The formation of corona streamers and breakdown (BD) streamers from the anode and cathode under the influence of a nonuniform electric field is analyzed. Charge concentrations are formed due to the accumulation of ions of opposite polarity, and the propagation of BD streamers due to the influence of these space charges (SCs) is illustrated. The final air BD is observed to be a combination of cathode- and anode-directed streamers. The velocity of the streamers decreases as they propagate through the low-field region, and the velocity of the anode-directed streamers is found to be less than that of the cathode-directed streamers. The computed FOVs are in agreement with the experimentally determined FOVs.
{"title":"Numerical Modeling of Streamer Propagation in a Nonuniform Electric Field to Assess the Lightning Impulse Flashover Voltage of Polymeric Insulators","authors":"M. Noorul Haque;K. Sunitha","doi":"10.1109/TPS.2025.3597884","DOIUrl":"https://doi.org/10.1109/TPS.2025.3597884","url":null,"abstract":"Assessing the dielectric withstand strength of every equipment in a power system is crucial for insulation coordination. The flashover voltage (FOV) of polymeric insulators due to a lightning impulse (LI) is computed by modeling the air discharge using air plasma chemistry and the movement of the charged species using the charge transport model. The formation of corona streamers and breakdown (BD) streamers from the anode and cathode under the influence of a nonuniform electric field is analyzed. Charge concentrations are formed due to the accumulation of ions of opposite polarity, and the propagation of BD streamers due to the influence of these space charges (SCs) is illustrated. The final air BD is observed to be a combination of cathode- and anode-directed streamers. The velocity of the streamers decreases as they propagate through the low-field region, and the velocity of the anode-directed streamers is found to be less than that of the cathode-directed streamers. The computed FOVs are in agreement with the experimentally determined FOVs.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2450-2457"},"PeriodicalIF":1.5,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061814","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 : 2025-08-22DOI: 10.1109/TPS.2025.3574812
Yong Bo;Xiaolong Pan;Xianmin Guo;Qingqing Deng;Wei Chen;Lixia Yang
This article establishes an electromagnetic scattering model for high-speed moving targets covered by a dusty plasma sheath, utilizing the Bhatnagar-Gross–Krook (BGK) collision model of fully ionized dusty plasma. The proposed Lorentz-shift-operator finite-difference time-domain (Lorentz-SO-FDTD) method is employed to compute the backscatter radar cross section (RCS) of complex blunt cone targets at varying velocities. Furthermore, considering the time-varying nature of electron density in dusty plasma, this study investigates the frequency-domain scattering properties of a moving blunt cone target coated with time-varying dusty plasma. The results indicate that the Doppler effect, caused by the target’s motion, influences both the echo signal and the backward RCS. Additionally, the time-varying characteristics of electron density modulate the scattering field of moving targets. The frequency components of the time-varying electron density and their higher order harmonics can be detected in the scattering field spectrum, leading to a reduction in the primary frequency energy of the echo signal spectrum.
{"title":"Research on Electromagnetic Scattering Characteristics of Moving Time-Varying Dusty Plasma Based on Lorentz-SO-FDTD Method","authors":"Yong Bo;Xiaolong Pan;Xianmin Guo;Qingqing Deng;Wei Chen;Lixia Yang","doi":"10.1109/TPS.2025.3574812","DOIUrl":"https://doi.org/10.1109/TPS.2025.3574812","url":null,"abstract":"This article establishes an electromagnetic scattering model for high-speed moving targets covered by a dusty plasma sheath, utilizing the Bhatnagar-Gross–Krook (BGK) collision model of fully ionized dusty plasma. The proposed Lorentz-shift-operator finite-difference time-domain (Lorentz-SO-FDTD) method is employed to compute the backscatter radar cross section (RCS) of complex blunt cone targets at varying velocities. Furthermore, considering the time-varying nature of electron density in dusty plasma, this study investigates the frequency-domain scattering properties of a moving blunt cone target coated with time-varying dusty plasma. The results indicate that the Doppler effect, caused by the target’s motion, influences both the echo signal and the backward RCS. Additionally, the time-varying characteristics of electron density modulate the scattering field of moving targets. The frequency components of the time-varying electron density and their higher order harmonics can be detected in the scattering field spectrum, leading to a reduction in the primary frequency energy of the echo signal spectrum.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2458-2466"},"PeriodicalIF":1.5,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061858","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 : 2025-08-22DOI: 10.1109/TPS.2025.3596401
Rajendra Kumar Verma;Shivendra Maurya;N. Kanagraj
The manuscript presents the implementation of epitrochoidal curve theory for the study and analysis of electron trajectories in the boundary conditions of the designed spatial harmonic magnetron (SHM). A model is created based on the epitrochoidal curve theory to study the trajectories of a particle/point with derived equations, offering insights into the understanding of magnetrons by a fundamental theoretical framework. The constants of the theory, namely “a,” “b,” “h,” and their correlation, have been analyzed. Constant “a” controls the expansion radius and thus relates to the dc voltage, constant “b” controls the gyration radius and relates to the magnetic field, and constant “h” controls the periodicity and perturbation of the trajectories and thus relates to the RF voltage. The model provides some derived equations enabling the mapping of these constants within the boundary constraints of the designed SHM to understand certain important phenomena in magnetrons and SHMs. The boundary condition solutions from the model provide the initial guesses of constants, which are further optimized by radial expansion study and trajectory analysis. The trajectories of the generated electron hub reveal the dominance of electron backbombardment phenomena at the cathode when the rotational radial vector rtot < rm mean radius, and anode current collection domination when the stationary radial vector rstat > rm mean radius. Thus, the model highlights the significance of the mean radius and optimizes the ratio of radial expansion constants “a” and “b” and the RF constant “h,” which plays a significant role in the working of magnetron physics. Using the model, the optimum values of the parameters for 22 spokes in SHM have been obtained as amax = 1.2342, amin = 0.6996, bmax = 0.0561, bmin = 0.0318, hmax $= pm 0.2960$ , and hmin $= =pm 0.0080$ .
{"title":"Electron Trajectories Analysis in Spatial Harmonic Magnetrons Using Epitrochoidal Curve Theory","authors":"Rajendra Kumar Verma;Shivendra Maurya;N. Kanagraj","doi":"10.1109/TPS.2025.3596401","DOIUrl":"https://doi.org/10.1109/TPS.2025.3596401","url":null,"abstract":"The manuscript presents the implementation of epitrochoidal curve theory for the study and analysis of electron trajectories in the boundary conditions of the designed spatial harmonic magnetron (SHM). A model is created based on the epitrochoidal curve theory to study the trajectories of a particle/point with derived equations, offering insights into the understanding of magnetrons by a fundamental theoretical framework. The constants of the theory, namely “a,” “b,” “h,” and their correlation, have been analyzed. Constant “a” controls the expansion radius and thus relates to the dc voltage, constant “b” controls the gyration radius and relates to the magnetic field, and constant “h” controls the periodicity and perturbation of the trajectories and thus relates to the RF voltage. The model provides some derived equations enabling the mapping of these constants within the boundary constraints of the designed SHM to understand certain important phenomena in magnetrons and SHMs. The boundary condition solutions from the model provide the initial guesses of constants, which are further optimized by radial expansion study and trajectory analysis. The trajectories of the generated electron hub reveal the dominance of electron backbombardment phenomena at the cathode when the rotational radial vector rtot < rm mean radius, and anode current collection domination when the stationary radial vector rstat > rm mean radius. Thus, the model highlights the significance of the mean radius and optimizes the ratio of radial expansion constants “a” and “b” and the RF constant “h,” which plays a significant role in the working of magnetron physics. Using the model, the optimum values of the parameters for 22 spokes in SHM have been obtained as <italic>a</i>max = 1.2342, <italic>a</i>min = 0.6996, <italic>b</i>max = 0.0561, <italic>b</i>min = 0.0318, <italic>h</i>max <inline-formula> <tex-math>$= pm 0.2960$ </tex-math></inline-formula>, and <italic>h</i>min <inline-formula> <tex-math>$= =pm 0.0080$ </tex-math></inline-formula>.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2248-2253"},"PeriodicalIF":1.5,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073345","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 : 2025-08-19DOI: 10.1109/TPS.2025.3596603
Saikat Chowdhury;Md Asifur Rahman;Mona Ghassemi
High-power density medium voltage direct current (MVdc) cables designed for electric aircraft applications must ensure reliable performance under extreme environmental conditions. To ensure safe and efficient operation, these cables need to exhibit strong resistance to partial discharge (PD) and arcing, which are critical factors affecting insulation integrity. Among the various multilayer multifunctional electrical insulation (MMEI) structures developed, the ARC-SC-T-MMEI described in this article has been selected for further investigation due to its multifunctional properties. We examine the PD behavior of the fabricated flat samples under atmospheric and low-pressure conditions to evaluate the impact of environmental variations on electrical performance. A comparative analysis of the PD characteristics is conducted using the Pearson correlation coefficient, which provides insights into how pressure influences discharge activity. The dielectric strength of the samples is assessed under both ac and dc voltage to evaluate their withstand capability and breakdown characteristics. A two-parameter Weibull distribution was employed for statistical comparison. In addition, we fabricate a cable prototype using the optimized MMEI system, analyzing its PD behavior and dielectric strength under ac and dc conditions at both atmospheric and low-pressure settings. These findings highlight the effectiveness of MMEI insulation in mitigating PD and enhancing dielectric strength, thereby advancing MVdc cable technology for electric aircraft applications.
{"title":"Comparative Analysis of Partial Discharge and Dielectric Strength of Multilayer Multifunctional Electrical Insulation (MMEI) Samples Under AC and DC Conditions at Atmospheric and Low Pressure","authors":"Saikat Chowdhury;Md Asifur Rahman;Mona Ghassemi","doi":"10.1109/TPS.2025.3596603","DOIUrl":"https://doi.org/10.1109/TPS.2025.3596603","url":null,"abstract":"High-power density medium voltage direct current (MVdc) cables designed for electric aircraft applications must ensure reliable performance under extreme environmental conditions. To ensure safe and efficient operation, these cables need to exhibit strong resistance to partial discharge (PD) and arcing, which are critical factors affecting insulation integrity. Among the various multilayer multifunctional electrical insulation (MMEI) structures developed, the ARC-SC-T-MMEI described in this article has been selected for further investigation due to its multifunctional properties. We examine the PD behavior of the fabricated flat samples under atmospheric and low-pressure conditions to evaluate the impact of environmental variations on electrical performance. A comparative analysis of the PD characteristics is conducted using the Pearson correlation coefficient, which provides insights into how pressure influences discharge activity. The dielectric strength of the samples is assessed under both ac and dc voltage to evaluate their withstand capability and breakdown characteristics. A two-parameter Weibull distribution was employed for statistical comparison. In addition, we fabricate a cable prototype using the optimized MMEI system, analyzing its PD behavior and dielectric strength under ac and dc conditions at both atmospheric and low-pressure settings. These findings highlight the effectiveness of MMEI insulation in mitigating PD and enhancing dielectric strength, thereby advancing MVdc cable technology for electric aircraft applications.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2401-2409"},"PeriodicalIF":1.5,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061967","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 : 2025-08-19DOI: 10.1109/TPS.2025.3597102
Pan Zhao;Shimin Yu;Yu Wang;Jingwen Xu;Hongyu Wang;Xianwu Jiang;Wei Jiang;Ya Zhang
The interaction between impedance matching networks and plasmas, characterized by nonlinear dynamics, plays a critical role in optimizing the absorption of power delivered to plasma loads and minimizing the reflected power, particularly in the context of capacitively coupled plasma (CCP) discharge mechanisms. In this study, we examine the discharge mechanism of the electronegative gas CF4 under the conditions where the circuit is properly matched. In addition, we incorporated a Boltzmann term to analyze the transition of discharge modes. The results indicate that iterative updates to the parameters of external circuit components can substantially diminish the reflection coefficient and find the optimal matching parameters. Comparison of operations with and without the activated matching network illustrates that plasma discharge is significantly enhanced with the matching network engaged, accompanied by a notable reduction in the time required to attain steady state. Investigation into the transition of discharge modes following matching has been conducted by varying initial voltages and pressures. The methodology presented in this article offers a valuable design reference for matching electronegative gas discharges within CCP systems.
{"title":"Automatic Numerical Impedance Matching of Single-Frequency Capacitively Coupled Plasmas in Carbon Tetrafluoride","authors":"Pan Zhao;Shimin Yu;Yu Wang;Jingwen Xu;Hongyu Wang;Xianwu Jiang;Wei Jiang;Ya Zhang","doi":"10.1109/TPS.2025.3597102","DOIUrl":"https://doi.org/10.1109/TPS.2025.3597102","url":null,"abstract":"The interaction between impedance matching networks and plasmas, characterized by nonlinear dynamics, plays a critical role in optimizing the absorption of power delivered to plasma loads and minimizing the reflected power, particularly in the context of capacitively coupled plasma (CCP) discharge mechanisms. In this study, we examine the discharge mechanism of the electronegative gas CF<sub>4</sub> under the conditions where the circuit is properly matched. In addition, we incorporated a Boltzmann term to analyze the transition of discharge modes. The results indicate that iterative updates to the parameters of external circuit components can substantially diminish the reflection coefficient and find the optimal matching parameters. Comparison of operations with and without the activated matching network illustrates that plasma discharge is significantly enhanced with the matching network engaged, accompanied by a notable reduction in the time required to attain steady state. Investigation into the transition of discharge modes following matching has been conducted by varying initial voltages and pressures. The methodology presented in this article offers a valuable design reference for matching electronegative gas discharges within CCP systems.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2177-2187"},"PeriodicalIF":1.5,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073213","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 : 2025-08-18DOI: 10.1109/TPS.2025.3596396
Wen Tian;Gongwei Wang;Nan Xiao;Ying Zhao;Weiqun Yuan;Ping Yan
Deposition occurs on the rail surface during the start-up stage of the launching process. These phenomenon influence the velocity of the armature, the acceleration of the armature and the launching stability of the launcher. In this article, 15 experiments with the linear current density of 19 kA/mm were carried out. The morphology of the rail surface at the armature start-up stage and the start-up time of the armature were measured by a 3-D laser profilometer and a high-speed camera, respectively. Three conclusions are obtained: 1) the morphology of the deposition layer on the surface of rails is high at the edges of armature-rail interface and low in the middle of interface because of nonuniform contact pressure and temperature; 2) as the number of experiments increases, the thickness of the deposition layer on the rail surface increases and then tends to stabilize; and 3) the start-up time of the armature increases rapidly, and then tends to stabilize. Moreover, to analyze the reason for the distribution of deposition layer on the rail surface observed during start-up stage in experiments, the contact pressure, current density and Joule heating were calculated. Results show that the contact pressure of the edges of the armature is relatively high, and these areas are also where high temperature is concentrated on the surface of the armature.
{"title":"Study on the Distribution of Deposition Layer on the Rail Surface and Its Influence on the Armature Start-up in Railgun","authors":"Wen Tian;Gongwei Wang;Nan Xiao;Ying Zhao;Weiqun Yuan;Ping Yan","doi":"10.1109/TPS.2025.3596396","DOIUrl":"https://doi.org/10.1109/TPS.2025.3596396","url":null,"abstract":"Deposition occurs on the rail surface during the start-up stage of the launching process. These phenomenon influence the velocity of the armature, the acceleration of the armature and the launching stability of the launcher. In this article, 15 experiments with the linear current density of 19 kA/mm were carried out. The morphology of the rail surface at the armature start-up stage and the start-up time of the armature were measured by a 3-D laser profilometer and a high-speed camera, respectively. Three conclusions are obtained: 1) the morphology of the deposition layer on the surface of rails is high at the edges of armature-rail interface and low in the middle of interface because of nonuniform contact pressure and temperature; 2) as the number of experiments increases, the thickness of the deposition layer on the rail surface increases and then tends to stabilize; and 3) the start-up time of the armature increases rapidly, and then tends to stabilize. Moreover, to analyze the reason for the distribution of deposition layer on the rail surface observed during start-up stage in experiments, the contact pressure, current density and Joule heating were calculated. Results show that the contact pressure of the edges of the armature is relatively high, and these areas are also where high temperature is concentrated on the surface of the armature.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 10","pages":"2682-2688"},"PeriodicalIF":1.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145290217","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 : 2025-08-18DOI: 10.1109/TPS.2025.3597132
Hui Jiang;Jinyu Tang;Ziyi Gong;Yufei Han;Yujiao Gao;Jiayu Li
To explore the discharge characteristics of annular surface dielectric barrier discharge (SDBD) and guide the optimization of plasma excitation sources, this study presents a comparative analysis of SDBD behavior driven by a high-frequency, high-voltage alternating current (ac) power supply and a nanosecond pulsed power supply. The voltage–current waveforms and discharge images were employed to systematically investigate the differences in discharge initiation, spatial morphology, and temporal evolution under the two excitation modes. The results show that nanosecond-pulsed SDBD exhibits reverse discharge during the voltage fall phase, whereas ac-driven SDBD exhibits an earlier discharge onset due to cumulative surface charge effects. As the voltage amplitude increases, both excitation modes produce more streamer channels and broader discharge areas. However, their discharge distribution modes differ significantly. Annular SDBD under ac excitation produces filamentary discharge localized along the edge of the high-voltage electrode, whereas under nanosecond pulse excitation, the separated-channel discharge channels are produced. These differences are attributed to variations in voltage rise time and surface charge dynamics. Nanosecond pulses create a stronger transient electric field, expanding discharge coverage. In ac-SDBD, residual electrons near the high-voltage electrode promote early breakdown in the next cycle. In contrast, reverse discharge under pulsed excitation reduces residual positive charge and delays the next discharge. Nevertheless, the high conductivity of established channels promotes repeated breakdown in the same location, maintaining separated-channel distribution.
{"title":"Comparison of Annular Surface Dielectric Barrier Discharge Characteristics Under AC and Nanosecond Pulsed Excitation","authors":"Hui Jiang;Jinyu Tang;Ziyi Gong;Yufei Han;Yujiao Gao;Jiayu Li","doi":"10.1109/TPS.2025.3597132","DOIUrl":"https://doi.org/10.1109/TPS.2025.3597132","url":null,"abstract":"To explore the discharge characteristics of annular surface dielectric barrier discharge (SDBD) and guide the optimization of plasma excitation sources, this study presents a comparative analysis of SDBD behavior driven by a high-frequency, high-voltage alternating current (ac) power supply and a nanosecond pulsed power supply. The voltage–current waveforms and discharge images were employed to systematically investigate the differences in discharge initiation, spatial morphology, and temporal evolution under the two excitation modes. The results show that nanosecond-pulsed SDBD exhibits reverse discharge during the voltage fall phase, whereas ac-driven SDBD exhibits an earlier discharge onset due to cumulative surface charge effects. As the voltage amplitude increases, both excitation modes produce more streamer channels and broader discharge areas. However, their discharge distribution modes differ significantly. Annular SDBD under ac excitation produces filamentary discharge localized along the edge of the high-voltage electrode, whereas under nanosecond pulse excitation, the separated-channel discharge channels are produced. These differences are attributed to variations in voltage rise time and surface charge dynamics. Nanosecond pulses create a stronger transient electric field, expanding discharge coverage. In ac-SDBD, residual electrons near the high-voltage electrode promote early breakdown in the next cycle. In contrast, reverse discharge under pulsed excitation reduces residual positive charge and delays the next discharge. Nevertheless, the high conductivity of established channels promotes repeated breakdown in the same location, maintaining separated-channel distribution.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"53 9","pages":"2168-2176"},"PeriodicalIF":1.5,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073301","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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