Major disruption poses a significant challenge to the safe operation of tokamaks, so disruption mitigation is a key problem to be solved in tokamak. Currently, the fundamental strategy of disruption mitigation involves actively injecting significant quantities of impurity gas or solids (such as neon, argon, deuterium, etc.) to generate sufficient radiation power for dissipating the plasma’s energy. The most commonly used disruption mitigation devices now are massive gas injection (MGI) and shattered pellet injection (SPI). However, The impurity injection rate is low, resulting in shallow deposits in the tokamak. Electromagnetic pellet injection (EMPI) is a relatively new generation of disruption mitigation system developed in J-TEXT Tokamak. The system is based on the electromagnetic rail run concept. It uses electromagnetic force to launch the armature with an impurity pellet. The EMPI has been tested several times and the speed of the pellet has broken through the speed of sound, far exceeding the launch speed of the traditional disruption mitigation system. This means impurity is deposited at a deeper location. However, the rail length of EMPI is too long and the rail ablation is serious, so it is a challenging problem to satisfy the tokamak installation space requirements. Therefore, based on the EMPI, an enhanced EMPI is designed, which increases the electromagnetic force by increasing the magnetic field intensity within the bore. This enables the rail length to be decreased to meet the specified condition. Building upon this foundation, various armature-rail coupling structures have been designed. These structures are subjected to COMSOL finite element simulation to determine which rail-armature interface exhibits minimal ablation, superior electrical contact, and maximal armature launch velocity. Subsequently, the optimal rail-armature coupling scheme is validated through an experimentation test.
{"title":"Optimization of Rail-Armature Coupling for the Enhanced Electromagnetic Pellet Injection in J-TEXT Tokamak","authors":"Zisen Nie;Zhongyong Chen;Wei Yan;Shengguo Xia;Yinlong Yu;Guinan Zou;Fanxi Liu;Yu Zhong;Jiangang Fang;Xun Zhou;Yuwei Sun;Yuan Sheng;You Li","doi":"10.1109/TPS.2024.3473029","DOIUrl":"https://doi.org/10.1109/TPS.2024.3473029","url":null,"abstract":"Major disruption poses a significant challenge to the safe operation of tokamaks, so disruption mitigation is a key problem to be solved in tokamak. Currently, the fundamental strategy of disruption mitigation involves actively injecting significant quantities of impurity gas or solids (such as neon, argon, deuterium, etc.) to generate sufficient radiation power for dissipating the plasma’s energy. The most commonly used disruption mitigation devices now are massive gas injection (MGI) and shattered pellet injection (SPI). However, The impurity injection rate is low, resulting in shallow deposits in the tokamak. Electromagnetic pellet injection (EMPI) is a relatively new generation of disruption mitigation system developed in J-TEXT Tokamak. The system is based on the electromagnetic rail run concept. It uses electromagnetic force to launch the armature with an impurity pellet. The EMPI has been tested several times and the speed of the pellet has broken through the speed of sound, far exceeding the launch speed of the traditional disruption mitigation system. This means impurity is deposited at a deeper location. However, the rail length of EMPI is too long and the rail ablation is serious, so it is a challenging problem to satisfy the tokamak installation space requirements. Therefore, based on the EMPI, an enhanced EMPI is designed, which increases the electromagnetic force by increasing the magnetic field intensity within the bore. This enables the rail length to be decreased to meet the specified condition. Building upon this foundation, various armature-rail coupling structures have been designed. These structures are subjected to COMSOL finite element simulation to determine which rail-armature interface exhibits minimal ablation, superior electrical contact, and maximal armature launch velocity. Subsequently, the optimal rail-armature coupling scheme is validated through an experimentation test.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3326-3334"},"PeriodicalIF":1.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600279","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}
Electromagnetic-driven projectile spin launching technology is an important way to achieve high-precision firing in the railgun, but there is still a lack of sufficient research on the structural design of the tail-connected revolving armature and experimental verification of the spin launching performance. In this article, first, a structural design scheme of a revolving armature with a tail-end connection is established and compared with the conventional armature structural design scheme. Second, the finite element calculation model of interference assembly is adopted, and the influence law of the improved armature structure parameters on the initial mechanical performance is obtained. The theoretical calculation results show that the change of armature structural parameters has a great influence on the contact area and little influence on the maximum equivalent stress. The contact force decreases sharply with the increase of the interference position L2, throat radius r, and crack width $c_w$ of the tail, and increases sharply with the increase of the tail thickness t and interference amount $Delta $ . Finally, the electromagnetic launching experiments with different launching energies are carried out on test projectiles with conventional armature and tail-connected armature. The experimental results show that the revolving armature with a tail-end connection can effectively improve the rotation speed, but it will also have some negative effects on the muzzle velocity and the contact state between the armature and the rail in the bore.
电磁驱动弹丸自旋发射技术是轨道炮实现高精度发射的重要途径，但目前在尾端连接旋转衔铁的结构设计和自旋发射性能的实验验证方面仍缺乏足够的研究。本文首先建立了尾端连接旋转电枢的结构设计方案，并与传统电枢结构设计方案进行了比较。其次，采用过盈装配的有限元计算模型，得出改进后的衔铁结构参数对初始机械性能的影响规律。理论计算结果表明，电枢结构参数的改变对接触面积影响较大，而对最大等效应力影响较小。接触力随尾部过盈位置 L2、喉管半径 r 和裂纹宽度 $c_w$ 的增大而急剧减小，随尾部厚度 t 和过盈量 $Delta $ 的增大而急剧增大。最后，对传统衔铁和尾部连接衔铁的试验弹进行了不同发射能量的电磁发射实验。实验结果表明，尾端连接的旋转衔铁能有效提高旋转速度，但也会对枪口速度和衔铁与枪膛内导轨的接触状态产生一些负面影响。
{"title":"Structural Design of Revolving Armature With Tail End Connection and Its Electromagnetic Launching Performance Verification","authors":"Yong Liu;Tao Zhang;Kai Huang;Yanhui Chen;Wanying Wang;Wei Fan;Wei Guo","doi":"10.1109/TPS.2024.3475750","DOIUrl":"https://doi.org/10.1109/TPS.2024.3475750","url":null,"abstract":"Electromagnetic-driven projectile spin launching technology is an important way to achieve high-precision firing in the railgun, but there is still a lack of sufficient research on the structural design of the tail-connected revolving armature and experimental verification of the spin launching performance. In this article, first, a structural design scheme of a revolving armature with a tail-end connection is established and compared with the conventional armature structural design scheme. Second, the finite element calculation model of interference assembly is adopted, and the influence law of the improved armature structure parameters on the initial mechanical performance is obtained. The theoretical calculation results show that the change of armature structural parameters has a great influence on the contact area and little influence on the maximum equivalent stress. The contact force decreases sharply with the increase of the interference position L2, throat radius r, and crack width \u0000<inline-formula> <tex-math>$c_w$ </tex-math></inline-formula>\u0000 of the tail, and increases sharply with the increase of the tail thickness t and interference amount \u0000<inline-formula> <tex-math>$Delta $ </tex-math></inline-formula>\u0000. Finally, the electromagnetic launching experiments with different launching energies are carried out on test projectiles with conventional armature and tail-connected armature. The experimental results show that the revolving armature with a tail-end connection can effectively improve the rotation speed, but it will also have some negative effects on the muzzle velocity and the contact state between the armature and the rail in the bore.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3335-3342"},"PeriodicalIF":1.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600227","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 : 2024-10-23DOI: 10.1109/TPS.2024.3474682
Zhizhen Liu;Xinjie Yu;Zhen Li;Bei Li
It is quite common to use multiple linear modules with asynchronous operation, e.g., the pulsed power supply (PPS) system for electromagnetic launch (EML), to provide higher power or the complex signal modulation function. Up to now, numerical simulation has been the only way to solve these problems but suffers from long running time and thus limits the large-scale optimization and control for these systems. This article proposes a rigorous port-equivalent order reduction method based on the Thevenin equivalence and short-circuit equivalence. This method can simplify the solution of multimodule linear circuits into the solution of multiple lower order circuits. If lower order circuits can be calculated analytically, the fully analytical calculation of the multimodule circuit can be realized. Otherwise, reducing the order can also greatly reduce the time of circuit simulation. On this basis, taking the meat grinder with a self-charged capacitor and thyristor (SECT) multimodule circuit as an example, its rapid and analytical calculation is demonstrated. Compared with the Simulink simulation, the results show that the method proposed in this article is about 50 times faster than the simulation, and the root-mean-square error (RMSE) is very small, which means that the calculation accuracy can well meet the requirements.
{"title":"Order Reduction and Rapid Calculation for Multimodule Linear Circuits","authors":"Zhizhen Liu;Xinjie Yu;Zhen Li;Bei Li","doi":"10.1109/TPS.2024.3474682","DOIUrl":"https://doi.org/10.1109/TPS.2024.3474682","url":null,"abstract":"It is quite common to use multiple linear modules with asynchronous operation, e.g., the pulsed power supply (PPS) system for electromagnetic launch (EML), to provide higher power or the complex signal modulation function. Up to now, numerical simulation has been the only way to solve these problems but suffers from long running time and thus limits the large-scale optimization and control for these systems. This article proposes a rigorous port-equivalent order reduction method based on the Thevenin equivalence and short-circuit equivalence. This method can simplify the solution of multimodule linear circuits into the solution of multiple lower order circuits. If lower order circuits can be calculated analytically, the fully analytical calculation of the multimodule circuit can be realized. Otherwise, reducing the order can also greatly reduce the time of circuit simulation. On this basis, taking the meat grinder with a self-charged capacitor and thyristor (SECT) multimodule circuit as an example, its rapid and analytical calculation is demonstrated. Compared with the Simulink simulation, the results show that the method proposed in this article is about 50 times faster than the simulation, and the root-mean-square error (RMSE) is very small, which means that the calculation accuracy can well meet the requirements.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3343-3351"},"PeriodicalIF":1.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600252","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 : 2024-10-16DOI: 10.1109/TPS.2024.3475012
Kai Jia;Xinjian Niu;Yinghui Liu;Jianwei Liu;Tianzhong Zhang;Hongfu Li;Zongzheng Sun
This article presents a study for a 250 GHz MW-level continuous mode gyrotron to satisfy the demand of DEMO for over 200 GHz high-power microwave sources. Through careful analysis, the new high-order mode TE45,18 is chosen as the operation mode. Simultaneously, the magnetic injection electron gun is researched to meet the operation requirement of the gyrotron. A novel curved gradient structure is proposed instead of the traditional linear folding structure for obtaining high-quality electronic beams. Through the linear theory and the time-dependent multimode self-consistent nonlinear theory of gyrotron, the detailed study of mode competition is conducted in the resonator cavity. The TE45,18 mode can maintain operational stability while suppressing other competition modes at the magnetic field of 9.9600 T, the operation voltage of 80 kV, and the beam current of 35 A. When considering the ideal electron beam, the output power is 1070 kW and the operation efficiency is 38.21%. The output power and operation efficiency are reduced to 1041 kW, and 37.17%, respectively, when considering the realistic electron beam from the magnetic injection gun (MIG) electron gun.
{"title":"Design and Nonlinear Theoretical Investigations on a 250 GHz MW-Level CW Demo Gyrotron With Realistic Electron Beam","authors":"Kai Jia;Xinjian Niu;Yinghui Liu;Jianwei Liu;Tianzhong Zhang;Hongfu Li;Zongzheng Sun","doi":"10.1109/TPS.2024.3475012","DOIUrl":"https://doi.org/10.1109/TPS.2024.3475012","url":null,"abstract":"This article presents a study for a 250 GHz MW-level continuous mode gyrotron to satisfy the demand of DEMO for over 200 GHz high-power microwave sources. Through careful analysis, the new high-order mode TE45,18 is chosen as the operation mode. Simultaneously, the magnetic injection electron gun is researched to meet the operation requirement of the gyrotron. A novel curved gradient structure is proposed instead of the traditional linear folding structure for obtaining high-quality electronic beams. Through the linear theory and the time-dependent multimode self-consistent nonlinear theory of gyrotron, the detailed study of mode competition is conducted in the resonator cavity. The TE45,18 mode can maintain operational stability while suppressing other competition modes at the magnetic field of 9.9600 T, the operation voltage of 80 kV, and the beam current of 35 A. When considering the ideal electron beam, the output power is 1070 kW and the operation efficiency is 38.21%. The output power and operation efficiency are reduced to 1041 kW, and 37.17%, respectively, when considering the realistic electron beam from the magnetic injection gun (MIG) electron gun.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3103-3110"},"PeriodicalIF":1.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600261","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}
A novel approach is suggested to enhance imaging sensitivity and refine the figure of merit (FoM) through the utilization of a long-range surface plasmon resonance (LRSPR) biosensor for the detection of water salinity concentration. This design integrates Teflon, copper (Cu), and a transition metal dichalcogenides (TMDCs) layer. By incorporating this composite coating, the biosensor aims to inhibit oxidation, boost biomolecule adsorption, and elevate imaging sensitivity, detection accuracy (DA), and FoM. Using MoS2, MoSe2, WS2, and WSe2 with the Teflon layer, the maximum achieved imaging sensitivities are 27651/RIU, 26501/RIU, 28059/RIU, 27209/RIU at 0% and 33245/RIU, 31458/RIU, 32424/RIU, 30472/RIU at 30%, water salinity concentration, respectively. Further, with the TMDCs layer, the maximum attained DA and FoM values with MoS2 are 33.33/° and 519.13/RIU, with MoSe2 are 50/° and 758.2/RIU, with WS2 are 50/° and 713.12/RIU, and with WSe2 are 50/° and 725.41/RIU, respectively. Additionally, the penetration depth (PD) of 566.12, 566.24, 493.77, and 508.3 nm at 0% and 700.14, 624.35, 570.28, and 569.94 nm at 30% salinity concentration is achieved. The numerical findings are compared to Teflon/Cytop layer-based LRSPR and conventional SPR (cSPR) sensors. We believe that this approach will have valuable applications in biological detection, medical diagnostics, and chemical analysis. While this work is solely based on simulations, we plan to conduct experimental studies in subsequent phases to further validate and refine the obtained numerical results.
{"title":"A Numerical Analysis for the Detection of Water Salinity Concentration Using Long-Range Surface Plasmon Resonance Biosensor With TMDCs-Teflon/Cytop","authors":"Rajeev Kumar;Shivam Singh;Lalit Garia;Bhargavi Chaudhary;Maneesh Kumar Singh;Santosh Kumar","doi":"10.1109/TPS.2024.3471636","DOIUrl":"https://doi.org/10.1109/TPS.2024.3471636","url":null,"abstract":"A novel approach is suggested to enhance imaging sensitivity and refine the figure of merit (FoM) through the utilization of a long-range surface plasmon resonance (LRSPR) biosensor for the detection of water salinity concentration. This design integrates Teflon, copper (Cu), and a transition metal dichalcogenides (TMDCs) layer. By incorporating this composite coating, the biosensor aims to inhibit oxidation, boost biomolecule adsorption, and elevate imaging sensitivity, detection accuracy (DA), and FoM. Using MoS2, MoSe2, WS2, and WSe2 with the Teflon layer, the maximum achieved imaging sensitivities are 27651/RIU, 26501/RIU, 28059/RIU, 27209/RIU at 0% and 33245/RIU, 31458/RIU, 32424/RIU, 30472/RIU at 30%, water salinity concentration, respectively. Further, with the TMDCs layer, the maximum attained DA and FoM values with MoS2 are 33.33/° and 519.13/RIU, with MoSe2 are 50/° and 758.2/RIU, with WS2 are 50/° and 713.12/RIU, and with WSe2 are 50/° and 725.41/RIU, respectively. Additionally, the penetration depth (PD) of 566.12, 566.24, 493.77, and 508.3 nm at 0% and 700.14, 624.35, 570.28, and 569.94 nm at 30% salinity concentration is achieved. The numerical findings are compared to Teflon/Cytop layer-based LRSPR and conventional SPR (cSPR) sensors. We believe that this approach will have valuable applications in biological detection, medical diagnostics, and chemical analysis. While this work is solely based on simulations, we plan to conduct experimental studies in subsequent phases to further validate and refine the obtained numerical results.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3136-3144"},"PeriodicalIF":1.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600107","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 : 2024-10-10DOI: 10.1109/TPS.2024.3469955
Yunhong Zhou;Zenan Chen;Yinfang Huang;Houwen Yang;Shuqin Li
With the extensive promotion of new energy generation in high-altitude regions, the demand for air circuit breakers (ACBs) has correspondingly increased, as they serve as essential protective devices in energy storage systems. However, the climate conditions in high-altitude areas pose challenges to the interruption performance of ACBs. This study focuses on ACBs and, based on the theory of magnetohydrodynamics (MHD), utilizes the finite element software Ansys Fluent to establish a 2-D dynamic arc simulation model. Simulation analyses are conducted at altitudes of 2, 3, 4, and 5 km. The findings reveal that as altitude increases, the average arc voltage decreases while the arcing time prolongs. In addition, the arc demonstrates faster movement before entering the arc-extinguishing splitter plates and slower movement afterward. Furthermore, through climate chamber simulation experiments, the arc current and voltage of the breaker in high-altitude environment are measured, and the erosion conditions of the arc-extinguishing splitter plates in post-test prototypes are used to validate the accuracy of the simulation model. The findings indicate that the simulation results are in good agreement with the experimental results. The construction of this simulation model helps compensate for the limitations of unclear observation of arc motion trajectories in experiments, facilitating the analysis of arc motion patterns and the identification of factors affecting the interruption performance of circuit breakers in different altitude environments. Thereby, this study can provide a theoretical basis and reference for the design of ACBs in high-altitude environment.
{"title":"Modeling and Analysis of Breaking Arc for AC Air Circuit Breakers in High-Altitude Environment","authors":"Yunhong Zhou;Zenan Chen;Yinfang Huang;Houwen Yang;Shuqin Li","doi":"10.1109/TPS.2024.3469955","DOIUrl":"https://doi.org/10.1109/TPS.2024.3469955","url":null,"abstract":"With the extensive promotion of new energy generation in high-altitude regions, the demand for air circuit breakers (ACBs) has correspondingly increased, as they serve as essential protective devices in energy storage systems. However, the climate conditions in high-altitude areas pose challenges to the interruption performance of ACBs. This study focuses on ACBs and, based on the theory of magnetohydrodynamics (MHD), utilizes the finite element software Ansys Fluent to establish a 2-D dynamic arc simulation model. Simulation analyses are conducted at altitudes of 2, 3, 4, and 5 km. The findings reveal that as altitude increases, the average arc voltage decreases while the arcing time prolongs. In addition, the arc demonstrates faster movement before entering the arc-extinguishing splitter plates and slower movement afterward. Furthermore, through climate chamber simulation experiments, the arc current and voltage of the breaker in high-altitude environment are measured, and the erosion conditions of the arc-extinguishing splitter plates in post-test prototypes are used to validate the accuracy of the simulation model. The findings indicate that the simulation results are in good agreement with the experimental results. The construction of this simulation model helps compensate for the limitations of unclear observation of arc motion trajectories in experiments, facilitating the analysis of arc motion patterns and the identification of factors affecting the interruption performance of circuit breakers in different altitude environments. Thereby, this study can provide a theoretical basis and reference for the design of ACBs in high-altitude environment.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3257-3269"},"PeriodicalIF":1.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600341","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 : 2024-10-10DOI: 10.1109/TPS.2024.3470905
Fengyun Wang;Zhenbao Liang;Zheng Zhou;Yuhan Zhang;Xiaoxia Du;Hua Li
Inactivation of bacteria by plasma is related to its active substances; the aim of this study is to investigate the impact of active substances’ spatial distribution on inactivation efficiency. In this study, a comparative analysis of the distribution and concentration of reactive oxygen and nitrogen species (RONSs) in the cross section of the plasma jet was conducted under different discharge voltages, working gas flow rates, and treatment distances. Then the impact of RONS distribution on the inactivation efficiency against Staphylococcus aureus (ATCC 25923) biofilm was analyzed. Experimental results demonstrated an influence of gas flow rates and treatment distances on RONS distribution. For instance, at the treatment distance of 3 mm, RONS distribution showed a solid circular shape at 0.4 standard liters per minute (SLM) and below, a double ring shape at 0.5 SLM, and a ring shape at 0.6 SLM. At 5 mm, the RONS distribution showed a solid circular shape at 0.8 SLM and below, a double ring shape at 0.9 SLM, and a ring shape at 0.9 SLM and above. The total redox concentration exhibited a positive correlation with the three physical parameters. Biofilm was treated for 100 s at a vertical position of approximately 3 mm. The inactivation of biofilm by the jet was slightly more efficient at 0.4 SLM (RONS was characterized by a low concentration of solid circular shape) compared to 0.8 SLM (high concentration of ring shape). Extending the treatment time to 300 s resulted in similar inactivation efficiency at 0.8 to 0.4 SLM.
{"title":"The Distribution of Active Substances and the Bacterial Inactivation Effect Induced by a Helium Microplasma","authors":"Fengyun Wang;Zhenbao Liang;Zheng Zhou;Yuhan Zhang;Xiaoxia Du;Hua Li","doi":"10.1109/TPS.2024.3470905","DOIUrl":"https://doi.org/10.1109/TPS.2024.3470905","url":null,"abstract":"Inactivation of bacteria by plasma is related to its active substances; the aim of this study is to investigate the impact of active substances’ spatial distribution on inactivation efficiency. In this study, a comparative analysis of the distribution and concentration of reactive oxygen and nitrogen species (RONSs) in the cross section of the plasma jet was conducted under different discharge voltages, working gas flow rates, and treatment distances. Then the impact of RONS distribution on the inactivation efficiency against Staphylococcus aureus (ATCC 25923) biofilm was analyzed. Experimental results demonstrated an influence of gas flow rates and treatment distances on RONS distribution. For instance, at the treatment distance of 3 mm, RONS distribution showed a solid circular shape at 0.4 standard liters per minute (SLM) and below, a double ring shape at 0.5 SLM, and a ring shape at 0.6 SLM. At 5 mm, the RONS distribution showed a solid circular shape at 0.8 SLM and below, a double ring shape at 0.9 SLM, and a ring shape at 0.9 SLM and above. The total redox concentration exhibited a positive correlation with the three physical parameters. Biofilm was treated for 100 s at a vertical position of approximately 3 mm. The inactivation of biofilm by the jet was slightly more efficient at 0.4 SLM (RONS was characterized by a low concentration of solid circular shape) compared to 0.8 SLM (high concentration of ring shape). Extending the treatment time to 300 s resulted in similar inactivation efficiency at 0.8 to 0.4 SLM.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3111-3117"},"PeriodicalIF":1.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600200","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}
Coplanar dielectric barrier discharge (CDBD) is widely used on the surface of materials because of its high plasma density and no requirement for the thickness of modified materials. In order to make the filamentary CDBD achieve suitable modification conditions under atmospheric pressure air conditions, a convenient and effective method for judging the macroscopic characteristics of discharge is urgently needed. In this article, a method of CDBD discharge analysis based on image processing is proposed, which characterizes the discharge uniformity by the saturation voltage obtained by binarization of the discharge image, the average pixel value, and the pixel variance of the discharge gray image. It makes up for the lack of identification of discharge uniformity by traditional diagnostic methods and can analyze discharge saturation voltage, discharge intensity, and uniformity efficiently and quickly. According to the above three parameters, we can further divide the discharge mode into fast discharge mode, slow discharge mode, and saturated discharge mode. The research in this article simplifies the process of determining the working conditions of surface modification using CDBD and provides a new idea for the scientific and quantitative study of the discharge characteristics of CDBD.
{"title":"Discharge Mode Analysis of Coplanar Dielectric Barrier Discharge Based on Image Processing","authors":"Qiaojue Liu;Mi You;Jieming Wang;Yangyang Chen;Zhanhe Guo;Shushu Zhu;Shuqun Wu","doi":"10.1109/TPS.2024.3466912","DOIUrl":"https://doi.org/10.1109/TPS.2024.3466912","url":null,"abstract":"Coplanar dielectric barrier discharge (CDBD) is widely used on the surface of materials because of its high plasma density and no requirement for the thickness of modified materials. In order to make the filamentary CDBD achieve suitable modification conditions under atmospheric pressure air conditions, a convenient and effective method for judging the macroscopic characteristics of discharge is urgently needed. In this article, a method of CDBD discharge analysis based on image processing is proposed, which characterizes the discharge uniformity by the saturation voltage obtained by binarization of the discharge image, the average pixel value, and the pixel variance of the discharge gray image. It makes up for the lack of identification of discharge uniformity by traditional diagnostic methods and can analyze discharge saturation voltage, discharge intensity, and uniformity efficiently and quickly. According to the above three parameters, we can further divide the discharge mode into fast discharge mode, slow discharge mode, and saturated discharge mode. The research in this article simplifies the process of determining the working conditions of surface modification using CDBD and provides a new idea for the scientific and quantitative study of the discharge characteristics of CDBD.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3166-3173"},"PeriodicalIF":1.3,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600253","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 : 2024-10-04DOI: 10.1109/TPS.2024.3464615
Pasquale Lucibello
We present an approach for the induction of the plasma axial current in a pinching device, that consists in the use of apertures in the external tubular conductor that surrounds the plasma itself. These apertures are spaced at regular intervals along the axis of the device and a radial parallel plate waveguide is coupled to each of them. To the end of each waveguide, a time-varying power source is connected and operated synchronously with all the others. We analyze the stability of the plasma motion in this device by using a model, the ideal device, in which the actual electromagnetic field is approximated by that generated by a time-varying azimuthal current distributed on the internal surface of the external conductor and a time-varying axial current flowing on the surface of the plasma. The desired or reference plasma motion inside the ideal device is a sequence of cylindrical equilibrium configurations coaxial with the external conductor that extends indefinitely. We analyze the stability of a reference trajectory, along which the plasma is compressed and expanded under the action of a screw magnetic field, by using a simplified set of linear equations of motion, based on the quasi 1-D flow of a gas, with electromagnetic forces complying with the quasi static approximation. Under the hypothesis that the azimuthal and axial currents are not perturbed, we show that an axial magnetic flux frozen in the plasma and an external conductor are necessary for stability. We also show that an axial magnetic field external to the plasma is not necessary for stability, so that, in a real device, its role could be limited to that of replenishing the embedded one, while the plasma is in contact or nearly in contact with the wall of its container. As opposed to previous theoretical investigations, we do not use the energy principle to prove stability/instability of a steady-state pinch without computing the eigenvalues of the linear equations of motion. On the contrary, for the cylindrical configuration analyzed, after decomposing the plasma motion in its main components, that is, massless, fluid, and string modes (the sausage and kink modes in previous different models), we compute the generalized masses and stiffnesses of the fluid and string modes. In the steady-state case, this allows us to compute their eigenvalues as a function of the geometric and magnetic parameters and then ascertain stability or instability of a specific pinch. By using these expressions, we also formulate necessary and/or sufficient conditions for stability, on the basis of which we are able to show the consistency of our results with the ones obtained in previous investigations. In particular, we derive a sufficient stability condition which is similar to the Kruskal-Shafronov necessary stability condition. We also formulate stability conditions in the time-varying case, which seems to be a novelty, except for what was done by this author in a recently published paper.
{"title":"On Axial Current Induction and Stability of a Pinch","authors":"Pasquale Lucibello","doi":"10.1109/TPS.2024.3464615","DOIUrl":"https://doi.org/10.1109/TPS.2024.3464615","url":null,"abstract":"We present an approach for the induction of the plasma axial current in a pinching device, that consists in the use of apertures in the external tubular conductor that surrounds the plasma itself. These apertures are spaced at regular intervals along the axis of the device and a radial parallel plate waveguide is coupled to each of them. To the end of each waveguide, a time-varying power source is connected and operated synchronously with all the others. We analyze the stability of the plasma motion in this device by using a model, the ideal device, in which the actual electromagnetic field is approximated by that generated by a time-varying azimuthal current distributed on the internal surface of the external conductor and a time-varying axial current flowing on the surface of the plasma. The desired or reference plasma motion inside the ideal device is a sequence of cylindrical equilibrium configurations coaxial with the external conductor that extends indefinitely. We analyze the stability of a reference trajectory, along which the plasma is compressed and expanded under the action of a screw magnetic field, by using a simplified set of linear equations of motion, based on the quasi 1-D flow of a gas, with electromagnetic forces complying with the quasi static approximation. Under the hypothesis that the azimuthal and axial currents are not perturbed, we show that an axial magnetic flux frozen in the plasma and an external conductor are necessary for stability. We also show that an axial magnetic field external to the plasma is not necessary for stability, so that, in a real device, its role could be limited to that of replenishing the embedded one, while the plasma is in contact or nearly in contact with the wall of its container. As opposed to previous theoretical investigations, we do not use the energy principle to prove stability/instability of a steady-state pinch without computing the eigenvalues of the linear equations of motion. On the contrary, for the cylindrical configuration analyzed, after decomposing the plasma motion in its main components, that is, massless, fluid, and string modes (the sausage and kink modes in previous different models), we compute the generalized masses and stiffnesses of the fluid and string modes. In the steady-state case, this allows us to compute their eigenvalues as a function of the geometric and magnetic parameters and then ascertain stability or instability of a specific pinch. By using these expressions, we also formulate necessary and/or sufficient conditions for stability, on the basis of which we are able to show the consistency of our results with the ones obtained in previous investigations. In particular, we derive a sufficient stability condition which is similar to the Kruskal-Shafronov necessary stability condition. We also formulate stability conditions in the time-varying case, which seems to be a novelty, except for what was done by this author in a recently published paper.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3270-3284"},"PeriodicalIF":1.3,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600280","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 : 2024-10-04DOI: 10.1109/TPS.2024.3467190
Afshin Shaygani;Kazimierz Adamiak;Mehrdad R. Kermani
A dielectric barrier discharge (DBD) plasma actuator for controlling airflow is proposed. It consists of diverging and converging nozzles, two concentric cylinders, and an actuator mounted in between the two cylinders. The actuator employs electrohydrodynamic (EHD) body force to induce an air jet within the air gap between the two cylinders, effectively creating a suction area while passing through the diverging nozzle, due to the Coanda effect. While merging with the air stream inside the inner cylinder, the Coanda jet effectively enhances the amplification of the airflow. The outflow rate is measured by a velocity sensor at the outlet and controlled by the plasma actuator. The control strategy is based on the active disturbance rejection control (ADRC) and compared to the baseline PID controller. The actuator was modeled by seamlessly linking two modeling platforms for a co-simulation study. The computational fluid dynamic (CFD) simulation of the plasma and airflow was carried out in the COMSOL multiphysics commercial software, and the control was implemented in Simulink. The DBD plasma model was based on the two-species model of discharge, and the electric body force, calculated from the plasma simulation, was used in the Navier-Stokes equation (NS) for the turbulent flow simulation using $k-omega $ model. The plasma-airflow system was analyzed using the input (the actuator voltage) and output (the outlet flow rate) data for the control design. Finally, the performance of the system of airflow control device was tested and discussed in the co-simulation process.
{"title":"Precision Airflow Control via EHD Actuator: A Co-Simulation and Control Design Case Study","authors":"Afshin Shaygani;Kazimierz Adamiak;Mehrdad R. Kermani","doi":"10.1109/TPS.2024.3467190","DOIUrl":"https://doi.org/10.1109/TPS.2024.3467190","url":null,"abstract":"A dielectric barrier discharge (DBD) plasma actuator for controlling airflow is proposed. It consists of diverging and converging nozzles, two concentric cylinders, and an actuator mounted in between the two cylinders. The actuator employs electrohydrodynamic (EHD) body force to induce an air jet within the air gap between the two cylinders, effectively creating a suction area while passing through the diverging nozzle, due to the Coanda effect. While merging with the air stream inside the inner cylinder, the Coanda jet effectively enhances the amplification of the airflow. The outflow rate is measured by a velocity sensor at the outlet and controlled by the plasma actuator. The control strategy is based on the active disturbance rejection control (ADRC) and compared to the baseline PID controller. The actuator was modeled by seamlessly linking two modeling platforms for a co-simulation study. The computational fluid dynamic (CFD) simulation of the plasma and airflow was carried out in the COMSOL multiphysics commercial software, and the control was implemented in Simulink. The DBD plasma model was based on the two-species model of discharge, and the electric body force, calculated from the plasma simulation, was used in the Navier-Stokes equation (NS) for the turbulent flow simulation using \u0000<inline-formula> <tex-math>$k-omega $ </tex-math></inline-formula>\u0000 model. The plasma-airflow system was analyzed using the input (the actuator voltage) and output (the outlet flow rate) data for the control design. Finally, the performance of the system of airflow control device was tested and discussed in the co-simulation process.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3153-3165"},"PeriodicalIF":1.3,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600106","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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