Plasma Pub Date : 2024-03-15 DOI: 10.3390/plasma7010013

A. Kozyrev, V. Tarasenko

{"title":"Optimal Conditions for the Generation of Runaway Electrons in High-Pressure Gases","authors":"A. Kozyrev, V. Tarasenko","doi":"10.3390/plasma7010013","DOIUrl":"https://doi.org/10.3390/plasma7010013","url":null,"abstract":"Runaway electron (RAE) generation in high-pressure gases is an important physical phenomenon that significantly influences discharge shapes and properties of initiated plasma. The diffuse discharges formed due to RAEs in the air and other gases at atmospheric pressure find wide applications. In the present review, theoretical and experimental results that explain the reason for RAE occurrence at high pressures are analyzed, and recommendations are given for the implementation of conditions under which the runaway electron beam (RAEB) with the highest current can be obtained at atmospheric pressure. The experimental results were obtained using subnanosecond, nanosecond, and submicrosecond generators, including those specially developed for runaway electron generation. The RAEBs were recorded using oscilloscopes and collectors with picosecond time resolution. To theoretically describe the phenomenon of continuous electron acceleration, the method of physical kinetics was used based on the Boltzmann kinetic equation that takes into account the minimum but sufficient number of elementary processes, including shock gas ionization and elastic electron scattering. The results of modeling allowed the main factors to be established that control the RAE appearance, the most important of which is electron scattering on neutral atoms and/or molecules. Theoretical modeling has allowed the influence of various parameters (including the voltage, pressure, gas type, and geometrical characteristics of the discharge gap) to be taken into account. The results of the research presented here allow RAE accelerators with desirable parameters to be developed and the possibility of obtaining diffuse discharges to be accessed under various conditions. The review consists of the Introduction, five sections, the Conclusion, and the References.","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"58 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140237408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Practical Model for the Calculation of Lateral Electromagnetic Loads in Tokamaks at Asymmetric Vertical Displacement Events (AVDEs) 非对称垂直位移事件 (AVDE) 时托卡马克侧向电磁载荷的实用计算模型

Plasma Pub Date : 2024-03-13 DOI: 10.3390/plasma7010012

Sergey Sadakov, F. Villone, Daniel Iglesias, Luis Maqueda, Jesus Almenara-Rescalvo, G. Rubinacci, S. Ventre

{"title":"Practical Model for the Calculation of Lateral Electromagnetic Loads in Tokamaks at Asymmetric Vertical Displacement Events (AVDEs)","authors":"Sergey Sadakov, F. Villone, Daniel Iglesias, Luis Maqueda, Jesus Almenara-Rescalvo, G. Rubinacci, S. Ventre","doi":"10.3390/plasma7010012","DOIUrl":"https://doi.org/10.3390/plasma7010012","url":null,"abstract":"This paper describes a new practical numerical model for the calculation of lateral electromagnetic (EM) loads in tokamaks during asymmetric vertical displacement events (AVDEs). The model combines key features of two recently reported trial models while avoiding their drawbacks. Their common basic feature is the superposition of two patterns of halo current: one perfectly symmetric and another perfectly anti-symmetric. This model combines the following features that have not been combined before (a) a helically distorted halo layer wrapping around core plasma, and (b) halo-to-wall interception belts slipping along plasma-facing walls. This combination almost doubles the lateral net forces. An AVDE creates significant lateral net moments. Being relatively modest at VDEs, the lateral moments become a dominant component of EM loads at AVDEs. The model carefully tracks the balance of net EM loads (zero total for the tokamak), as a necessary condition for the consequent numerical simulation of the tokamak’s dynamic response. This balance is needed as well for the development of tokamak monitoring algorithms and simulators. In order to decouple from the current uncertainties in the interpretation and simulation of AVDE physics, the model does not simulate AVDE evolution but uses it as an input assumption based on the existing interpretation and simulation of AVDE physics. This means the model is to be used in a manner of parametric study, at widely varied input assumptions on AVDE evolution and severity. Parametric results will fill a library of ready-for-use waveforms of asymmetric EM loads (distributed and total) at tokamak structures and coils, so that the physics community may point to specific variants for subsequent engineering analysis. This article presents the first practical contribution to this AVDE library.","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140248294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Plasma-Driven Sciences: Exploring Complex Interactions at Plasma Boundaries 等离子体驱动科学：探索等离子体边界的复杂相互作用

Plasma Pub Date : 2024-02-27 DOI: 10.3390/plasma7010011

K. Ishikawa, K. Koga, Noriyasu Ohno

引用次数: 0

A Physical Metric for Inertial Confinement Fusion Capsules 惯性约束聚变舱的物理度量标准

Plasma Pub Date : 2024-02-21 DOI: 10.3390/plasma7010010

B. Cheng, Paul A. Bradley

引用次数: 0

Rapid Access to Empirical Impact Ionization Cross Sections for Atoms and Ions across the Periodic Table 快速获取元素周期表中原子和离子的经验撞击电离截面

Plasma Pub Date : 2024-01-30 DOI: 10.3390/plasma7010008

S. Fritzsche, Liguang Jiao, Giorgio Visentin

{"title":"Rapid Access to Empirical Impact Ionization Cross Sections for Atoms and Ions across the Periodic Table","authors":"S. Fritzsche, Liguang Jiao, Giorgio Visentin","doi":"10.3390/plasma7010008","DOIUrl":"https://doi.org/10.3390/plasma7010008","url":null,"abstract":"Electron-impact ionization (EII) processes are essential for modelling high-temperature plasma in quite different research areas, from astrophysics to material science to plasma and fusion research and in several places elsewhere. In most, if not all, of these fields, partial and total EII cross sections are required, and often for a good range of electron energies, in order to determine, for instance, the level population of ions and spectral line intensities in plasma under both local and non-local thermodynamic equilibrium conditions. To obey these needs, various kinds of semi-empirical EII cross sections have been applied in practice, often simply because of the large computational demands in dealing explicitly with two free electrons within the continuum. Here, we expand Jac, the Jena Atomic Calculator, to provide such empirical EII cross sections for (most) atoms and ions across the periodic table. Five empirical models from the recent literature have been implemented to support a simple and rapid access to the partial EII cross sections for electrons from a (partly filled) shell (nℓ)q as well as the total ionization cross sections. We here restrict ourselves to the direct part of the EII cross section, whereas the impact excitation of electrons with subsequent autoionization and the resonant electron capture with double autoionization have been left aside in this first implementation. Rapid access to the (direct) EII cross sections will help already to better understand the role of electron-impact processes in the diagnostics of fusion plasma or the interpretation of astrophysical spectra.","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"134 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140483307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Plasma Treatment of Different Biodegradable Polymers: A Method to Enhance Wettability and Adhesion Properties for Use in Industrial Packaging 不同生物可降解聚合物的等离子处理：增强工业包装中的润湿性和粘合性的方法

Plasma Pub Date : 2024-01-26 DOI: 10.3390/plasma7010007

E. Vassallo, M. Pedroni, Marco Aloisio, Silvia Maria Pietralunga, Riccardo Donnini, F. Saitta, Dimitrios Fessas

{"title":"Plasma Treatment of Different Biodegradable Polymers: A Method to Enhance Wettability and Adhesion Properties for Use in Industrial Packaging","authors":"E. Vassallo, M. Pedroni, Marco Aloisio, Silvia Maria Pietralunga, Riccardo Donnini, F. Saitta, Dimitrios Fessas","doi":"10.3390/plasma7010007","DOIUrl":"https://doi.org/10.3390/plasma7010007","url":null,"abstract":"Biodegradable polymers (poly(butylene succinate (PBS)), poly(butylene adipate terephthalate (PBAT)) and poly(lactic acid)/poly(butylene adipate terephthalate (PLA/PBAT)) blend) were treated in radiofrequency (13.56 MHz) low-pressure (10 Pa) oxygen with argon post-crosslinking plasma to enhance wettability and adhesion properties. Surface morphology and roughness modification caused by plasma exposure were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface chemical modifications of plasma-treated samples were evaluated by Fourier Transform infrared spectroscopy (FTIR). Due to the limited durability of plasma activation, the hydrophobic recovery was evaluated by water contact angle (WCA) measurements. The ageing effect was measured over 15 days in order to assess this kind of treatment as a potential industrial scalable method to increase biodegradable polymers hydrophilic properties for food packaging applications. The effects of polymer activation on its weight loss were also determined. Differential scanning calorimetry (DSC) analysis was used to study the effect of plasma treatment on the thermal properties of the polymers, while the crystallinity was investigated by X-ray diffraction (XRD).","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"75 6-7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140494392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermal Plasma Spheroidization and Characterization of Stainless Steel Powders Using Direct Current Plasma Technology 利用直流等离子体技术对不锈钢粉末进行热等离子体球化和表征

Plasma Pub Date : 2024-01-23 DOI: 10.3390/plasma7010006

P. Iovane, C. Borriello, Giuseppe Pandolfi, S. Portofino, Gabriella Rametta, Loredana Tammaro, Nicola Fedele, S. Galvagno

{"title":"Thermal Plasma Spheroidization and Characterization of Stainless Steel Powders Using Direct Current Plasma Technology","authors":"P. Iovane, C. Borriello, Giuseppe Pandolfi, S. Portofino, Gabriella Rametta, Loredana Tammaro, Nicola Fedele, S. Galvagno","doi":"10.3390/plasma7010006","DOIUrl":"https://doi.org/10.3390/plasma7010006","url":null,"abstract":"The production of spherical powders has recently registered a boost due to the need to fabricate new printing materials for Additive Manufacturing applications, from polymers and resins to metals and ceramics. Among these materials, stainless steels powders play a leading role, since they are widely used in industry and everyday life; indeed, micron-sized spherical stainless steel powders have specific characteristics and are considered as one of the best candidates for Additive Manufacturing systems and for application in a wide range of sectors. In this paper, stainless steel 316 L powders were used to explore and identify the best process parameters of a thermal plasma process able to produce spherical powders for Additive Manufacturing applications. X-ray Diffraction, Scanning Electron Microscopy, Particle Size Distribution and Flowability analysis were performed to characterize reagents and products. Powders with a high circularity (>0.8) and improved flowability (<30 s/50 g) were successfully obtained. The collected results were compared with data available from the literature to identify the potential use of the spherical produced powders.","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"9 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139604355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatial Distribution Analyses of Axially Long Plasmas under a Multi-Cusp Magnetic Field Using a Kinetic Particle Simulation Code KEIO-MARC 利用动力学粒子模拟代码 KEIO-MARC 分析多尖顶磁场下轴向长等离子体的空间分布情况

Plasma Pub Date : 2024-01-22 DOI: 10.3390/plasma7010005

Ryota Nishimura, T. Seino, Keigo Yoshimura, Hiroyuki Takahashi, Akinobu Matsuyama, Kazuo Hoshino, Tetsutarou Oishi, Kenji Tobita

{"title":"Spatial Distribution Analyses of Axially Long Plasmas under a Multi-Cusp Magnetic Field Using a Kinetic Particle Simulation Code KEIO-MARC","authors":"Ryota Nishimura, T. Seino, Keigo Yoshimura, Hiroyuki Takahashi, Akinobu Matsuyama, Kazuo Hoshino, Tetsutarou Oishi, Kenji Tobita","doi":"10.3390/plasma7010005","DOIUrl":"https://doi.org/10.3390/plasma7010005","url":null,"abstract":"To realize the development of a long plasma source with a uniform electron density distribution in the axial direction, the spatial distribution of plasma under a multi-cusp magnetic field was analyzed using a KEIO-MARC code. Considering a cylindrical plasma source with an axial length of 3000 mm and a cross-sectional diameter of 100 mm, in which the filament electrode was the electron source, the electron density distribution was calculated using the residual magnetic flux density, Bres, and the number of permanent magnets installed at different locations surrounding the device, Nmag, as design parameters. The results show that both Bres and Nmag improved the uniformity of the electron density distribution in the axial direction. The maximum axial electron density decreased with increasing Nmag and increased with increasing Bres. These trends can be explained by considering the nature of the multi-cusp field, where particles are mainly confined to the field-free region (FFR) near the center of the plasma column, and the loss of particles due to radial particle transport. The use of multiple filaments at intervals shorter than the plasma decay length dramatically improved axial uniformity. To further improve axial uniformity, the filament length and FFR must be properly set so that electrons are emitted inside the FFR.","PeriodicalId":509984,"journal":{"name":"Plasma","volume":"26 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139608930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polystyrene (PS) Degradation Induced by Nanosecond Electric Discharge in Air in Contact with PS/Water 空气中与聚苯乙烯（PS）/水接触的纳秒放电引起的聚苯乙烯（PS）降解

Plasma Pub Date : 2024-01-16 DOI: 10.3390/plasma7010004

Aurélie Zamo, Catherine Rond, A. Hamdan

引用次数: 0

A Tutorial on the One-Dimensional Theory of Electron-Beam Space-Charge Effect and Steady-State Virtual Cathode 电子束空间电荷效应和稳态虚拟阴极的一维理论教程

Plasma Pub Date : 2024-01-05 DOI: 10.3390/plasma7010003

Weihua Jiang

引用次数: 0

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