To investigate the degradation processes and the mechanisms of the insulation performance of epoxy composites under pulse voltage, a study was conducted using techniques such as Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to explore the pulsed breakdown, dynamic mechanical evolution, and surface chemical structural change characteristics. Additionally, molecular dynamics (MD) were employed to investigate the movements of molecules at the microscopic level. The cumulative damage effect and the temperature increase effect of the system during the pulse triggering time led to decreases in the thermodynamic properties of the material, thus decreasing the electrical properties. Under experimental voltages (32–45 kV), the microscale surface morphology, surface chemical state, and thermodynamic performance characteristics of composites were almost unaffected by a single pulse. The composites experienced three stages of cumulative damage: pore/microcrack generation, fusion, and rapid fusion (late insulation life stage). Breakdown occurred extremely quickly after the late insulation life stage. At the microscopic level, the polar functional groups and polar chain segments of the system were influenced by the electric field and elevated temperature. This influence intensified molecular chain motion, thereby accelerating the processes of dissociation of molecular functional groups and rupture of chemical bonds. With an increase in the cumulative pulse count, the rupture of crosslinked network chemical bonds in composites intensified, forming local low-concentration disturbed regions while generating OH groups and other reactive groups, impacting the chemical structure of the material. This change further led to a reduction in the thermodynamic performance, accelerating the degradation of the insulation performance.
{"title":"Study on the Cumulative Damage Behaviors and Microscopic Mechanisms of Epoxy Composite Materials Under a Microsecond Pulse Voltage With a Low Duty Cycle","authors":"Fei Yin;Lijun Yang;Yuan Yuan;Hanwen Zheng;Chen Chen","doi":"10.1109/TPS.2024.3460800","DOIUrl":"https://doi.org/10.1109/TPS.2024.3460800","url":null,"abstract":"To investigate the degradation processes and the mechanisms of the insulation performance of epoxy composites under pulse voltage, a study was conducted using techniques such as Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to explore the pulsed breakdown, dynamic mechanical evolution, and surface chemical structural change characteristics. Additionally, molecular dynamics (MD) were employed to investigate the movements of molecules at the microscopic level. The cumulative damage effect and the temperature increase effect of the system during the pulse triggering time led to decreases in the thermodynamic properties of the material, thus decreasing the electrical properties. Under experimental voltages (32–45 kV), the microscale surface morphology, surface chemical state, and thermodynamic performance characteristics of composites were almost unaffected by a single pulse. The composites experienced three stages of cumulative damage: pore/microcrack generation, fusion, and rapid fusion (late insulation life stage). Breakdown occurred extremely quickly after the late insulation life stage. At the microscopic level, the polar functional groups and polar chain segments of the system were influenced by the electric field and elevated temperature. This influence intensified molecular chain motion, thereby accelerating the processes of dissociation of molecular functional groups and rupture of chemical bonds. With an increase in the cumulative pulse count, the rupture of crosslinked network chemical bonds in composites intensified, forming local low-concentration disturbed regions while generating OH groups and other reactive groups, impacting the chemical structure of the material. This change further led to a reduction in the thermodynamic performance, accelerating the degradation of the insulation performance.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4348-4360"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797920","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 : 2024-10-01DOI: 10.1109/TPS.2024.3460473
Wenchao Li;Yingjie Chen;Rongyao Fu;Ping Yan;Youlong Wang;Yaohong Sun
A pulsed alternator (PA) is an important pulse power source capable of driving many types of loads. For electromagnetic rail launcher load, the ideal driving current is a flat top wave. However, the discharge current of the PA will decline, resulting in the inability to maintain a flat top during pulse discharge. Therefore, an optimization method of discharge current based on excitation compensation is proposed and compared it with the traditional method of adjusting the trigger angle (ATA) in this article. First, the relationship between field current and discharge current is analyzed theoretically, and the optimization method is verified. Second, three optimization methods: ATA, separate-excitation compensation (SEC1), and self-excitation compensation (SEC2) were compared. Then, a comparative analysis was conducted on the optimization strategies for the combination of multimethods. Finally, the PA inductance parameters were extracted by using the finite element method (FEM), and the FEM and circuit coupling simulation and the circuit simulation were compared to verify the accuracy of the circuit model and the superiority of the optimization strategies. The results show that all three optimization methods have obvious merits and demerits. The optimization strategies can balance the merits and demerits of a single method and obtain great benefits at small costs. Especially the ATA + SEC2 and ATA + SEC1+ SEC2 optimization strategies are the most prominent. The former does not require external energy compared to the latter, at the cost of a slightly higher field current peak; the latter can achieve the recovery of residual energy in the rails for excitation compensation in the next pulse discharge, at the cost of requiring a set of devices for the residual energy recovery in the rails.
脉冲交流发电机（PA）是一种重要的脉冲电源，能够驱动多种负载。对于电磁轨道发射器负载，理想的驱动电流是平顶波。然而，脉冲交流发电机的放电电流会下降，导致在脉冲放电过程中无法保持平顶波。因此，本文提出了一种基于激励补偿的放电电流优化方法，并与传统的调整触发角（ATA）方法进行了比较。首先，从理论上分析了场电流和放电电流之间的关系，并验证了优化方法。第二，三种优化方法：ATA、分离励磁补偿（SEC1）和自励磁补偿（SEC2）三种优化方法进行了比较。然后，对多种方法组合的优化策略进行了比较分析。最后，使用有限元法（FEM）提取了功率放大器的电感参数，并将有限元法和电路耦合仿真与电路仿真进行了比较，以验证电路模型的准确性和优化策略的优越性。结果表明，三种优化方法都有明显的优缺点。优化策略可以平衡单一方法的优缺点，以较小的代价获得较大的收益。其中尤以 ATA + SEC2 和 ATA + SEC1+ SEC2 优化策略最为突出。与后者相比，前者不需要外部能量，但代价是场电流峰值略高；后者可以实现轨道残余能量的回收，用于下一次脉冲放电时的励磁补偿，但代价是需要一套用于轨道残余能量回收的装置。
{"title":"Discharge Current Optimization of Multiphase Pulsed Alternator Based on Excitation Compensation","authors":"Wenchao Li;Yingjie Chen;Rongyao Fu;Ping Yan;Youlong Wang;Yaohong Sun","doi":"10.1109/TPS.2024.3460473","DOIUrl":"https://doi.org/10.1109/TPS.2024.3460473","url":null,"abstract":"A pulsed alternator (PA) is an important pulse power source capable of driving many types of loads. For electromagnetic rail launcher load, the ideal driving current is a flat top wave. However, the discharge current of the PA will decline, resulting in the inability to maintain a flat top during pulse discharge. Therefore, an optimization method of discharge current based on excitation compensation is proposed and compared it with the traditional method of adjusting the trigger angle (ATA) in this article. First, the relationship between field current and discharge current is analyzed theoretically, and the optimization method is verified. Second, three optimization methods: ATA, separate-excitation compensation (SEC1), and self-excitation compensation (SEC2) were compared. Then, a comparative analysis was conducted on the optimization strategies for the combination of multimethods. Finally, the PA inductance parameters were extracted by using the finite element method (FEM), and the FEM and circuit coupling simulation and the circuit simulation were compared to verify the accuracy of the circuit model and the superiority of the optimization strategies. The results show that all three optimization methods have obvious merits and demerits. The optimization strategies can balance the merits and demerits of a single method and obtain great benefits at small costs. Especially the ATA + SEC2 and ATA + SEC1+ SEC2 optimization strategies are the most prominent. The former does not require external energy compared to the latter, at the cost of a slightly higher field current peak; the latter can achieve the recovery of residual energy in the rails for excitation compensation in the next pulse discharge, at the cost of requiring a set of devices for the residual energy recovery in the rails.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3201-3211"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600277","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 : 2024-10-01DOI: 10.1109/TPS.2024.3463178
Rami Ahmad El-Nabulsi
The phenomenon of solitons characterized by nonlinear structures is widely studied in the literature due to their important implications in various fields of sciences and engineering, mainly space plasma physics. These solitons are described by nonlinear evolution equations, such as the highly nonlinear Korteweg-de Vries (KdV) and Zakharov-Kuznetsov equations. Different methods are used to search soliton solutions to these nonlinear dynamical equations and the solutions obtained are determined in general as the integration of exponential, hyperbolic, trigonometric, and rational functions. The types of solitons obtained depend on the number of related parameters, the structure of nonlinearly dispersive terms, and on the type and number of various involutions imposed on the dynamical system. In this study, we show that particular types of solitons, such as the periodic solitons, compactons, singular periodic solitons, cuspons, bright kink, and bell-shaped solitons can be obtained with and without the presence of charged space debris in at low-Earth orbital plasma region without imposing external conditions or adding higher order nonlinear terms. Our model is based on the fractional actionlike variational approach which is described in general by the fractional Boltzmann equation (FBE) that models the evolution of the particle distribution function.
{"title":"A Fractional Model to Study Soliton in Presence of Charged Space Debris at Low-Earth Orbital Plasma Region","authors":"Rami Ahmad El-Nabulsi","doi":"10.1109/TPS.2024.3463178","DOIUrl":"https://doi.org/10.1109/TPS.2024.3463178","url":null,"abstract":"The phenomenon of solitons characterized by nonlinear structures is widely studied in the literature due to their important implications in various fields of sciences and engineering, mainly space plasma physics. These solitons are described by nonlinear evolution equations, such as the highly nonlinear Korteweg-de Vries (KdV) and Zakharov-Kuznetsov equations. Different methods are used to search soliton solutions to these nonlinear dynamical equations and the solutions obtained are determined in general as the integration of exponential, hyperbolic, trigonometric, and rational functions. The types of solitons obtained depend on the number of related parameters, the structure of nonlinearly dispersive terms, and on the type and number of various involutions imposed on the dynamical system. In this study, we show that particular types of solitons, such as the periodic solitons, compactons, singular periodic solitons, cuspons, bright kink, and bell-shaped solitons can be obtained with and without the presence of charged space debris in at low-Earth orbital plasma region without imposing external conditions or adding higher order nonlinear terms. Our model is based on the fractional actionlike variational approach which is described in general by the fractional Boltzmann equation (FBE) that models the evolution of the particle distribution function.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4671-4693"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797910","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 : 2024-10-01DOI: 10.1109/TPS.2024.3400364
Bofeng Zhu;Xiao Zhang;Tongyang Zhao;Tao Ma;Junyong Lu
Air-core compensated pulse alternator (compulsator) is an important technical approach to realize the miniaturization of pulse power supply (PPS) for electromagnetic launch (EML). When it discharges, the internal components especially windings are faced with extreme conditions of transient strong coupling of electromagnetic, force, and temperature fields, so efficient thermal management design is one of the key technologies for its safe and reliable operation. In this article, a new thermal analysis method based on fluid-structure coupling and distributed convective heat transfer coefficient is proposed. Compared with the traditional calculation method which uses constant convective heat transfer coefficient, it has higher accuracy and is conducive to more precise analysis of continuous discharge temperature distribution and active cooling effect under extreme conditions. Combined with a design example of the GW scale compulsator, the thermal analysis results of forced air cooling and active water cooling are compared and analyzed. The research conclusions have important reference significance for guiding the overall design of the compulsator, and the research methods can be extended to other electrical thermal analysis occasions.
{"title":"Thermal Analysis of Compulsator Based on Fluid-Structure Coupling and Distributed Convective Heat Transfer Coefficient","authors":"Bofeng Zhu;Xiao Zhang;Tongyang Zhao;Tao Ma;Junyong Lu","doi":"10.1109/TPS.2024.3400364","DOIUrl":"https://doi.org/10.1109/TPS.2024.3400364","url":null,"abstract":"Air-core compensated pulse alternator (compulsator) is an important technical approach to realize the miniaturization of pulse power supply (PPS) for electromagnetic launch (EML). When it discharges, the internal components especially windings are faced with extreme conditions of transient strong coupling of electromagnetic, force, and temperature fields, so efficient thermal management design is one of the key technologies for its safe and reliable operation. In this article, a new thermal analysis method based on fluid-structure coupling and distributed convective heat transfer coefficient is proposed. Compared with the traditional calculation method which uses constant convective heat transfer coefficient, it has higher accuracy and is conducive to more precise analysis of continuous discharge temperature distribution and active cooling effect under extreme conditions. Combined with a design example of the GW scale compulsator, the thermal analysis results of forced air cooling and active water cooling are compared and analyzed. The research conclusions have important reference significance for guiding the overall design of the compulsator, and the research methods can be extended to other electrical thermal analysis occasions.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3193-3200"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600267","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 : 2024-10-01DOI: 10.1109/TPS.2024.3431942
G. A. Filgueira;R. S. Pessoa;R. K. Yamamoto;C. Alves;A. S. da Silva Sobrinho
This study employed an inverted reactor approach to activate tap water (TW) using effluent bubbles derived from a gliding arc discharge (GAD). Optical emission spectroscopy (OES) analysis revealed the dominant presence of nitrogen species and oxygen radicals within specified spectral ranges. The physicochemical attributes of the plasma-activated TW (PATW) remained consistent, highlighting the efficacy of the reactor’s bubbling system. Through UV-Vis spectrophotometry and pH analysis, the notable observation was the stabilizing influence of hydrogen peroxide (H2O2) and positive hydrogen ions (H+) during the initial activation phases (75 min), which played a significant role in maintaining mildly alkaline pH. Energy efficiency metrics demonstrated a decline up to 1.25 h of activation, with subsequent stabilization. Our research outcomes further emphasize the efficacy of GAD, shedding light on its significant potential in optimizing the water activation process.
{"title":"Plasma-Activated Tap Water by Gliding Arc Discharge Through Bubbles Using an Inverted Reactor Approach","authors":"G. A. Filgueira;R. S. Pessoa;R. K. Yamamoto;C. Alves;A. S. da Silva Sobrinho","doi":"10.1109/TPS.2024.3431942","DOIUrl":"https://doi.org/10.1109/TPS.2024.3431942","url":null,"abstract":"This study employed an inverted reactor approach to activate tap water (TW) using effluent bubbles derived from a gliding arc discharge (GAD). Optical emission spectroscopy (OES) analysis revealed the dominant presence of nitrogen species and oxygen radicals within specified spectral ranges. The physicochemical attributes of the plasma-activated TW (PATW) remained consistent, highlighting the efficacy of the reactor’s bubbling system. Through UV-Vis spectrophotometry and pH analysis, the notable observation was the stabilizing influence of hydrogen peroxide (H2O2) and positive hydrogen ions (H+) during the initial activation phases (75 min), which played a significant role in maintaining mildly alkaline pH. Energy efficiency metrics demonstrated a decline up to 1.25 h of activation, with subsequent stabilization. Our research outcomes further emphasize the efficacy of GAD, shedding light on its significant potential in optimizing the water activation process.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3127-3135"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600190","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 : 2024-10-01DOI: 10.1109/TPS.2024.3444706
Robert Kerr;Sergio Lozano-Perez;David E. J. Armstrong;Martin S. Meier;Michael P. Moody;Yevhen Zayachuk;Anna Widdowson
When manufacturing W for fusion applications, it is crucial to consider microstructural features, such as grain shape and size, dislocation densities, distribution of defects, and impurities. These factors have a significant impact on a component’s lifetime in the fusion environment. This work provides valuable insights into the potential failure mechanisms that impact bulk W components. A bulk W lamella, which was manufactured for the JET divertor as part of the ITER-like wall (ILW) campaigns, was studied. A crack network had formed on the plasma-facing surface of the sample due to electrical discharge machining (EDM). The cracks predominantly propagated around larger grains due to grain misorientation and impurities. Notably, P and Fe were observed via atom probe tomography (APT), which appears to promote the diffusion of O. The results suggest that the initiation of crack propagation is linked to the nucleation of voids which exhibit behavior akin to KSiAl-doped W wires, involving diffusion-driven processes. O signal found inside some of the voids, confirmed by analytical transmission electron microscopy (TEM), suggests W oxide had formed on the internal surface, supporting the theory of oxidation-assisted void formation. It is, therefore, extremely important to consider the distribution of impurities and preexisting surface damage in W plasma-facing components (PFCs) before they are placed in the vessel.
{"title":"Cracking and Void Formation in Bulk W Components Manufactured for JET ITER-Like Wall","authors":"Robert Kerr;Sergio Lozano-Perez;David E. J. Armstrong;Martin S. Meier;Michael P. Moody;Yevhen Zayachuk;Anna Widdowson","doi":"10.1109/TPS.2024.3444706","DOIUrl":"https://doi.org/10.1109/TPS.2024.3444706","url":null,"abstract":"When manufacturing W for fusion applications, it is crucial to consider microstructural features, such as grain shape and size, dislocation densities, distribution of defects, and impurities. These factors have a significant impact on a component’s lifetime in the fusion environment. This work provides valuable insights into the potential failure mechanisms that impact bulk W components. A bulk W lamella, which was manufactured for the JET divertor as part of the ITER-like wall (ILW) campaigns, was studied. A crack network had formed on the plasma-facing surface of the sample due to electrical discharge machining (EDM). The cracks predominantly propagated around larger grains due to grain misorientation and impurities. Notably, P and Fe were observed via atom probe tomography (APT), which appears to promote the diffusion of O. The results suggest that the initiation of crack propagation is linked to the nucleation of voids which exhibit behavior akin to KSiAl-doped W wires, involving diffusion-driven processes. O signal found inside some of the voids, confirmed by analytical transmission electron microscopy (TEM), suggests W oxide had formed on the internal surface, supporting the theory of oxidation-assisted void formation. It is, therefore, extremely important to consider the distribution of impurities and preexisting surface damage in W plasma-facing components (PFCs) before they are placed in the vessel.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4054-4062"},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10702432","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797938","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 : 2024-09-30DOI: 10.1109/TPS.2024.3459809
Martin E. Stiehler;Konstantinos Georgarakis
Novel alloys like metallic glasses (MGs) hold the potential to revolutionize many scientific and industrial sectors including nuclear fusion (NF). These metallic materials with amorphous atomic structure possess outstanding mechanical properties in combination with high corrosion resistance and high radiation tolerance. They can be made and shaped in unique ways impossible for conventional crystalline materials. MGs also offer high compositional flexibility and can be tailored to various specific applications. Here, we give a brief overview on how the fusion sector can benefit from MGs and, as examples, highlight some specific use cases. We also outline a pathway for the future development of MGs specifically designed for the extreme environments occurring in NF.
{"title":"Metallic Glasses–Novel Materials for Applications in Nuclear Fusion","authors":"Martin E. Stiehler;Konstantinos Georgarakis","doi":"10.1109/TPS.2024.3459809","DOIUrl":"https://doi.org/10.1109/TPS.2024.3459809","url":null,"abstract":"Novel alloys like metallic glasses (MGs) hold the potential to revolutionize many scientific and industrial sectors including nuclear fusion (NF). These metallic materials with amorphous atomic structure possess outstanding mechanical properties in combination with high corrosion resistance and high radiation tolerance. They can be made and shaped in unique ways impossible for conventional crystalline materials. MGs also offer high compositional flexibility and can be tailored to various specific applications. Here, we give a brief overview on how the fusion sector can benefit from MGs and, as examples, highlight some specific use cases. We also outline a pathway for the future development of MGs specifically designed for the extreme environments occurring in NF.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4161-4166"},"PeriodicalIF":1.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810522","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 : 2024-09-30DOI: 10.1109/TPS.2024.3452482
Lingfeng Zhang;Fei Wang;Hongbing Liu;Zuming Liu;Huan Li
Spectral diagnosis is the primary approach to understanding the properties and behaviors of thermal plasmas. The partition function cutoff and the lowering of ionization energy directly influence the results of spectral radiation calculation. To investigate the effects of two factors on spectral analysis, this study uses aluminum plasma as an example, commonly found in laser ablation and processing. Four research schemes were designed (using two partition function cutoff criteria-NIST data/Griem’s theory, considering/not considering the lowering of ionization energy) to calculate the partition functions, particle number densities, and line radiation coefficients of aluminum atoms and ions over a temperature range of 3000–30000 K. The results indicate that the lowering of ionization energy significantly influences the radiation properties of aluminum plasma, compared to the influence of the cutoff criteria. Therefore, accurate radiation calculations require consideration of the reduction in ionization energy. Moreover, using the straightforward approach (NIST data) for the cutoff criteria can yield temperature values with sufficient accuracy, thus simplifying the calculation of the partition function.
光谱诊断是了解热等离子体特性和行为的主要方法。分区函数截止点和电离能的降低直接影响光谱辐射计算的结果。为了研究这两个因素对光谱分析的影响，本研究以激光烧蚀和加工中常见的铝等离子体为例。研究设计了四种研究方案（使用两种分区函数截止准则-NIST 数据/Griem 理论，考虑/不考虑电离能的降低）来计算铝原子和离子在 3000-30000 K 温度范围内的分区函数、粒子数密度和线辐射系数。因此，精确的辐射计算需要考虑电离能的降低。此外，使用直接的方法（NIST 数据）来确定截止标准可以得到足够精确的温度值，从而简化了分区函数的计算。
{"title":"Influences of Partition Function Cutoff Versus Lowering of Ionization Energy on Spectroscopic Temperature Measurement in Aluminum Plasmas","authors":"Lingfeng Zhang;Fei Wang;Hongbing Liu;Zuming Liu;Huan Li","doi":"10.1109/TPS.2024.3452482","DOIUrl":"https://doi.org/10.1109/TPS.2024.3452482","url":null,"abstract":"Spectral diagnosis is the primary approach to understanding the properties and behaviors of thermal plasmas. The partition function cutoff and the lowering of ionization energy directly influence the results of spectral radiation calculation. To investigate the effects of two factors on spectral analysis, this study uses aluminum plasma as an example, commonly found in laser ablation and processing. Four research schemes were designed (using two partition function cutoff criteria-NIST data/Griem’s theory, considering/not considering the lowering of ionization energy) to calculate the partition functions, particle number densities, and line radiation coefficients of aluminum atoms and ions over a temperature range of 3000–30000 K. The results indicate that the lowering of ionization energy significantly influences the radiation properties of aluminum plasma, compared to the influence of the cutoff criteria. Therefore, accurate radiation calculations require consideration of the reduction in ionization energy. Moreover, using the straightforward approach (NIST data) for the cutoff criteria can yield temperature values with sufficient accuracy, thus simplifying the calculation of the partition function.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3174-3184"},"PeriodicalIF":1.3,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600276","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 : 2024-09-25DOI: 10.1109/TPS.2024.3459481
Li Sun;Ming Xu;Xian-Pin Sun;Zeng-Yao Li
Recent studies have shown that the thermal emission from the cathode plays a crucial role in the basic research on microarc discharge. In this work, a 1-D implicit particle-in-cell coupled with the Monte Carlo collision (PIC-MCC) method is adopted to simulate thermal emission-driven microarc discharge at atmospheric pressure. Two thermal emission models—thermionic emission (TE) model and thermofield emission (TFE) model—are applied to contrast and analyze the particle transport phenomena of thermal microplasma. Considering that the local electric field near the cathode affects the current densities and ionization can create sufficient space charge to modify the electric field, different current densities at the cathode and their contribution to the total current densities are evaluated under various conditions, including cathode temperatures ( ${T} _{text {C}} = 2500~sim ~3500$ K), applied voltages ( ${U} = 1~sim ~30$ V), and gap sizes ( ${d} = 10~sim ~100~mu $ m). The electric field, maximum number density, and spatially averaged temperature of charged particles are also examined to study the interaction between thermal emission and discharge physics. Furthermore, the effects of secondary electron emission are analyzed to accurately predict electron emission in the microarc discharge. The results indicate the difference between thermal microplasma generated by TE and TFE becomes more pronounced as the gap size decreases, the cathode temperature increases, and the applied voltage increases due to the enhanced field emission (FE). In addition, gas breakdown occurs at a relatively lower voltage of 17 V for the two emission models because of the ion-enhancement effect. There exists a maximum at ${d} = 30~mu $ m in current density at the cathode due to the difference between collision mean free path of electron and gap sizes. Besides, the secondary electron emission becomes more pronounced at higher cathode temperatures and larger secondary electron emission coefficients.
{"title":"Numerical Simulation of Kinetic Characteristics of Thermal Emission-Driven Argon Microarc Discharge at Atmospheric Pressure","authors":"Li Sun;Ming Xu;Xian-Pin Sun;Zeng-Yao Li","doi":"10.1109/TPS.2024.3459481","DOIUrl":"https://doi.org/10.1109/TPS.2024.3459481","url":null,"abstract":"Recent studies have shown that the thermal emission from the cathode plays a crucial role in the basic research on microarc discharge. In this work, a 1-D implicit particle-in-cell coupled with the Monte Carlo collision (PIC-MCC) method is adopted to simulate thermal emission-driven microarc discharge at atmospheric pressure. Two thermal emission models—thermionic emission (TE) model and thermofield emission (TFE) model—are applied to contrast and analyze the particle transport phenomena of thermal microplasma. Considering that the local electric field near the cathode affects the current densities and ionization can create sufficient space charge to modify the electric field, different current densities at the cathode and their contribution to the total current densities are evaluated under various conditions, including cathode temperatures (\u0000<inline-formula> <tex-math>${T} _{text {C}} = 2500~sim ~3500$ </tex-math></inline-formula>\u0000 K), applied voltages (\u0000<inline-formula> <tex-math>${U} = 1~sim ~30$ </tex-math></inline-formula>\u0000 V), and gap sizes (\u0000<inline-formula> <tex-math>${d} = 10~sim ~100~mu $ </tex-math></inline-formula>\u0000m). The electric field, maximum number density, and spatially averaged temperature of charged particles are also examined to study the interaction between thermal emission and discharge physics. Furthermore, the effects of secondary electron emission are analyzed to accurately predict electron emission in the microarc discharge. The results indicate the difference between thermal microplasma generated by TE and TFE becomes more pronounced as the gap size decreases, the cathode temperature increases, and the applied voltage increases due to the enhanced field emission (FE). In addition, gas breakdown occurs at a relatively lower voltage of 17 V for the two emission models because of the ion-enhancement effect. There exists a maximum at \u0000<inline-formula> <tex-math>${d} = 30~mu $ </tex-math></inline-formula>\u0000m in current density at the cathode due to the difference between collision mean free path of electron and gap sizes. Besides, the secondary electron emission becomes more pronounced at higher cathode temperatures and larger secondary electron emission coefficients.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 8","pages":"3246-3256"},"PeriodicalIF":1.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600260","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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