Pub Date : 2024-04-09DOI: 10.1088/2058-6272/ad3c6d
Qingmei Xiao, A. Mao, Xianglei He, Jitong Zou, Xiaoyi Yang, Mengmeng Sun, Feng Li, Pengfei Tang, Tianchun Zhou, Xiaogang Wang
The Space Plasma Environment Research Facility (SPERF) for ground simulation of space plasma environment is a key component of Space Environment Simulation Research Infrastructure (SESRI), a major national science and technology infrastructure for fundamental researches. It is designed to investigate outstanding issues in space plasma environment, such as energetic particles acceleration, transport, and interaction with electromagnetic waves, as well as magnetic reconnection processes, in the magnetospheric plasmas, etc. Tail-Research EXperiment (TREX) is part of the SPERF for laboratory studies of space physics relevant to magnetic reconnection, dipolarization and hydromagnetic waves excitation in the magnetotail. SPERF-TREX is designed to carry out three types of experiments: the tail plasmoid for magnetic reconnection, dipolarization front formation, and magnetohydrodynamic waves excited by high speed plasma jet. In this paper, the scientific goals and three scenarios of SPERF-TREX for typical processes in space plasmas are presented, and experimental plans for SPERF-TREX are also reviewed, together with plasma sources applied to generate the plasma with desired parameters and various magnetic configurations.
用于空间等离子体环境地面模拟的空间等离子体环境研究设施（Space Plasma Environment Research Facility，SPERF）是空间环境模拟研究基础设施（Space Environment Simulation Research Infrastructure，SESRI）的重要组成部分，SESRI是国家重大基础研究科技基础设施。其目的是研究空间等离子体环境中的突出问题，如磁层等离子体中的高能粒子加速、传输、与电磁波的相互作用以及磁重联过程等。磁尾研究实验（TREX）是 SPERF 的一部分，用于实验室研究与磁尾中的磁重联、双极化和水电磁波激发有关的空间物理学。SPERF-TREX 实验旨在开展三类实验：磁再连接的尾部质点、偶极化前沿的形成以及高速等离子体喷流激发的磁流体波。本文介绍了 SPERF-TREX 的科学目标和针对空间等离子体典型过程的三种方案，还回顾了 SPERF-TREX 的实验计划，以及用于产生具有所需参数和各种磁性配置的等离子体的等离子体源。
{"title":"Conceptual Design of the Tail Research EXperiment in Space Plasma Environment Research Facility (SPERF-TREX)","authors":"Qingmei Xiao, A. Mao, Xianglei He, Jitong Zou, Xiaoyi Yang, Mengmeng Sun, Feng Li, Pengfei Tang, Tianchun Zhou, Xiaogang Wang","doi":"10.1088/2058-6272/ad3c6d","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3c6d","url":null,"abstract":"\u0000 The Space Plasma Environment Research Facility (SPERF) for ground simulation of space plasma environment is a key component of Space Environment Simulation Research Infrastructure (SESRI), a major national science and technology infrastructure for fundamental researches. It is designed to investigate outstanding issues in space plasma environment, such as energetic particles acceleration, transport, and interaction with electromagnetic waves, as well as magnetic reconnection processes, in the magnetospheric plasmas, etc. Tail-Research EXperiment (TREX) is part of the SPERF for laboratory studies of space physics relevant to magnetic reconnection, dipolarization and hydromagnetic waves excitation in the magnetotail. SPERF-TREX is designed to carry out three types of experiments: the tail plasmoid for magnetic reconnection, dipolarization front formation, and magnetohydrodynamic waves excited by high speed plasma jet. In this paper, the scientific goals and three scenarios of SPERF-TREX for typical processes in space plasmas are presented, and experimental plans for SPERF-TREX are also reviewed, together with plasma sources applied to generate the plasma with desired parameters and various magnetic configurations.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"36 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140727206","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}
The liquid Li divertor is one of promising alternatives for the future fusion device. In this work, a new divertor model is proposed, which is processed by 3D-printing technology to accurately control the size of the internal capillary structure. At the steady-state heat load of 10 MW/m2, the thermal stress of tungsten target is within the bearing range of tungsten by FE simulation. In order to evaluate the wicking ability of capillary structure, the wicking process at 600 °C was simulated by Fluent. Its result was identical with the corresponding experiments. Within 1 s, liquid lithium was wicked to target surface by the capillary structure of the target and quickly spread on the target surface. During the wicking process, the average wicking mass rate of lithium would reach 0.062 g/s, which could even supplement the evaporation requirement of liquid lithium under ＞950 °C environment. Irradiation experiments under different plasma discharge currents were carried out in linear plasma device (SCU-PSI), and the evolution process of the vapor cloud during plasma irradiation was analyzed. It was found that the target temperature tends to plateau in spite of gradually increased input current, indicating that the vapor shielding effect is gradually enhanced. The irradiation experiment also confirmed that 3D-printing tungsten structure has better heat consumption performance than that of tungsten mesh structure and multichannel structure. These results reveal the application potential and feasibility of 3D-printing porous capillary structure in plasma-facing components(PFCs) and provide a reference for further liquid-solid combined target designs.
{"title":"The design of 3D-printing liquid lithium divertor target plate and its interaction with high-density plasma","authors":"Congcong Yuan, Zongbiao Ye, Jianxing Liu, Hengxin Guo, Yichao Peng, Jiashu Liao, Bo Chen, Jianjun Chen, Hongbin Wang, Jianjun Wei, Xiujie Zhang, Fujun Gou","doi":"10.1088/2058-6272/ad3c6b","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3c6b","url":null,"abstract":"\u0000 The liquid Li divertor is one of promising alternatives for the future fusion device. In this work, a new divertor model is proposed, which is processed by 3D-printing technology to accurately control the size of the internal capillary structure. At the steady-state heat load of 10 MW/m2, the thermal stress of tungsten target is within the bearing range of tungsten by FE simulation. In order to evaluate the wicking ability of capillary structure, the wicking process at 600 °C was simulated by Fluent. Its result was identical with the corresponding experiments. Within 1 s, liquid lithium was wicked to target surface by the capillary structure of the target and quickly spread on the target surface. During the wicking process, the average wicking mass rate of lithium would reach 0.062 g/s, which could even supplement the evaporation requirement of liquid lithium under ＞950 °C environment. Irradiation experiments under different plasma discharge currents were carried out in linear plasma device (SCU-PSI), and the evolution process of the vapor cloud during plasma irradiation was analyzed. It was found that the target temperature tends to plateau in spite of gradually increased input current, indicating that the vapor shielding effect is gradually enhanced. The irradiation experiment also confirmed that 3D-printing tungsten structure has better heat consumption performance than that of tungsten mesh structure and multichannel structure. These results reveal the application potential and feasibility of 3D-printing porous capillary structure in plasma-facing components(PFCs) and provide a reference for further liquid-solid combined target designs.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"33 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140725350","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}
In the design realm of fusion power supplies, structural component plays a pivotal role in ensuring the safety of fusion device. To verify the reliability of converter structure design in Comprehensive Research Facility for Fusion Technology (CRAFT), the meticulous analysis of the converter's dynamic impact is carefully analyzed based on the worst fault current (400 kA), firstly. Subsequently, the thermal stress analysis based on maximum allowable steady-state temperature is finished, and the equivalent thermal stress, thermal deformation, maximum shear stress of single bridge arm and whole converter are studied. Furthermore, a simple research method of current sharing characteristics of bridge arm with multi-thyristor parallel connection is proposed by combination Simplorer with Q3D in ANSYS. The results show that the current sharing characteristics is great. Finally, the structural design has been meticulously tailored to meet the established requirements.
{"title":"Analysis and verification of electrodynamic force, thermal stress and current sharing for CRAFT converter structure design","authors":"Zhongma Wang, Chaoyi Shi, Xiuqing Zhang, Wenwu Lu, Sheng Zhang, Xianhe Gao, Tao Xu, XingXing Shao, Liansheng Huang","doi":"10.1088/2058-6272/ad3c6c","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3c6c","url":null,"abstract":"\u0000 In the design realm of fusion power supplies, structural component plays a pivotal role in ensuring the safety of fusion device. To verify the reliability of converter structure design in Comprehensive Research Facility for Fusion Technology (CRAFT), the meticulous analysis of the converter's dynamic impact is carefully analyzed based on the worst fault current (400 kA), firstly. Subsequently, the thermal stress analysis based on maximum allowable steady-state temperature is finished, and the equivalent thermal stress, thermal deformation, maximum shear stress of single bridge arm and whole converter are studied. Furthermore, a simple research method of current sharing characteristics of bridge arm with multi-thyristor parallel connection is proposed by combination Simplorer with Q3D in ANSYS. The results show that the current sharing characteristics is great. Finally, the structural design has been meticulously tailored to meet the established requirements.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"23 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140722001","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}
Pub Date : 2024-04-07DOI: 10.1088/2058-6272/ad3b9b
Liang Guo, Xin Li, Qi Li, Sanwei Li, Xin Hu, Jin Li, B. Deng, Keli Deng, Qiangqiang Wang, Z. Cao, Lifei Hou, Xinsen Che, H. Du, T. Xu, Xiaoan He, Zhi-chao Li, Xiaohua Jiang, Wei Jiang, C. Zheng, Wudi Zheng, Peng Song, Yongkun Ding, Dong Yang, Jia-Min Yang
An experiment on 100 kJ laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums. These hohlraums are designed to possess one open end and one laser entrance hole (LEH) with different diameters, which would or not result in the blocking of the LEH. An x-ray streak camera that is set at 16 degrees with respect to the hohlraum axis is applied to acquire the time-resolved x-ray images from the open end. Based on the images, we can study the evolutions of the wall plasma, corona bubble plasma and LEH plasma simultaneously through an equivalent view field of hohlraum interior. Multi-group flat response x-ray detectors are applied to measure the x-ray fluxes. In order to understand these characteristics, our two-dimensional radiation hydrodynamic code is used to simulate the experimental results. For the accuracy of reproduction, dielectronic recombination and two parameter corrections are applied in our code. Based on the comparison between experiments and simulations, we quantitatively understand the blocking process of LEH and the motion effects of other plasmas. The calibrated code is beneficial to design the gas-filled hohlraum in a nearby parameter space, especially the limit size of LEH.
我们在 100 kJ 激光设备上进行了一项实验，以研究来自充气圆柱形穹隆内不同区域的等离子体的动力特征和辐射特性。这些穹隆设计成具有一个开口端和一个不同直径的激光入口孔（LEH），这将导致或不导致 LEH 的堵塞。将 X 射线条纹照相机设置为与光室轴线成 16 度，以便从开口端获取时间分辨 X 射线图像。根据这些图像，我们可以通过霍尔姆内部的等效视场，同时研究壁等离子体、电晕泡等离子体和 LEH 等离子体的演变过程。多组平面响应 X 射线探测器用于测量 X 射线通量。为了了解这些特性，我们使用了二维辐射流体力学代码来模拟实验结果。为了保证再现的准确性，我们在代码中应用了介子电子重组和两个参数修正。基于实验和模拟的对比，我们定量地理解了 LEH 的阻塞过程和其他等离子体的运动效应。校准后的代码有利于在附近的参数空间内设计充气霍尔姆，特别是 LEH 的极限尺寸。
{"title":"Studies on the motion and radiation of interior plasmas in gas-filled hohlraums with different laser entrance hole sizes","authors":"Liang Guo, Xin Li, Qi Li, Sanwei Li, Xin Hu, Jin Li, B. Deng, Keli Deng, Qiangqiang Wang, Z. Cao, Lifei Hou, Xinsen Che, H. Du, T. Xu, Xiaoan He, Zhi-chao Li, Xiaohua Jiang, Wei Jiang, C. Zheng, Wudi Zheng, Peng Song, Yongkun Ding, Dong Yang, Jia-Min Yang","doi":"10.1088/2058-6272/ad3b9b","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3b9b","url":null,"abstract":"\u0000 An experiment on 100 kJ laser facility is performed to study the motive features and radiation properties of plasmas from different areas inside gas-filled cylindrical hohlraums. These hohlraums are designed to possess one open end and one laser entrance hole (LEH) with different diameters, which would or not result in the blocking of the LEH. An x-ray streak camera that is set at 16 degrees with respect to the hohlraum axis is applied to acquire the time-resolved x-ray images from the open end. Based on the images, we can study the evolutions of the wall plasma, corona bubble plasma and LEH plasma simultaneously through an equivalent view field of hohlraum interior. Multi-group flat response x-ray detectors are applied to measure the x-ray fluxes. In order to understand these characteristics, our two-dimensional radiation hydrodynamic code is used to simulate the experimental results. For the accuracy of reproduction, dielectronic recombination and two parameter corrections are applied in our code. Based on the comparison between experiments and simulations, we quantitatively understand the blocking process of LEH and the motion effects of other plasmas. The calibrated code is beneficial to design the gas-filled hohlraum in a nearby parameter space, especially the limit size of LEH.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"54 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140733506","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}
Pub Date : 2024-04-01DOI: 10.1088/2058-6272/ad3951
Hao Yu, Jixing Cai, Hongtao Mao, Yunpeng Wang, Yi Li, Shun Li
This study examines the impact of variations in side-blowing airflow velocity on plasma generation, combustion wave propagation mechanisms, and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser. The airflow rate and pulse delay are the main experimental variables. The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing. The experimental results demonstrate that the expansion velocity of the plasma and combustion wave is influenced differently by the side-blowing airflow at different airflow rates (0.2 Ma, 0.4 Ma, and 0.6 Ma). As the flow rate of the side-blow air stream increases, the initial expansion velocity of the plasma and combustion wave gradually decreases, and the side-blow air stream increasingly suppresses the plasma. It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action. Therefore, the side-blown airflow alone cannot completely clear the plasma. Depending on the delay conditions, the pressure of the side-blowing airflow and the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as double combustion wave when using a nanosecond pulse laser. Both simulation and experimental results are consistent, indicating the potential for further exploration of fused silica targets in the laser field.
本研究探讨了侧吹气流速度变化对等离子体生成、燃烧波传播机制以及毫秒-纳秒联合脉冲激光诱导熔融石英表面损伤的影响。气流速率和脉冲延迟是主要的实验变量。利用超快时间分辨光学阴影技术记录了等离子体运动的演变过程。实验结果表明，在不同的气流速率（0.2 Ma、0.4 Ma 和 0.6 Ma）下，等离子体的膨胀速度和燃烧波受侧吹气流的影响不同。随着侧吹气流流速的增加，等离子体和燃烧波的初始膨胀速度逐渐减小，侧吹气流对等离子体的抑制作用越来越大。值得注意的是，在联合脉冲激光作用过程中，目标蒸气总是会形成并电离成等离子体。因此，仅靠侧吹气流无法完全清除等离子体。根据延迟条件的不同，侧吹气流的压力以及反轫致辐射吸收和靶表面吸收机制的影响会在使用纳秒脉冲激光时导致一种被称为双重燃烧波的现象。模拟和实验结果是一致的，这表明在激光领域进一步探索熔融石英靶的潜力是巨大的。
{"title":"Study on the influence of side-blown airflow velocity on plasma and combustion waves generated from fused silica induced by combined pulse laser","authors":"Hao Yu, Jixing Cai, Hongtao Mao, Yunpeng Wang, Yi Li, Shun Li","doi":"10.1088/2058-6272/ad3951","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3951","url":null,"abstract":"\u0000 This study examines the impact of variations in side-blowing airflow velocity on plasma generation, combustion wave propagation mechanisms, and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser. The airflow rate and pulse delay are the main experimental variables. The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing. The experimental results demonstrate that the expansion velocity of the plasma and combustion wave is influenced differently by the side-blowing airflow at different airflow rates (0.2 Ma, 0.4 Ma, and 0.6 Ma). As the flow rate of the side-blow air stream increases, the initial expansion velocity of the plasma and combustion wave gradually decreases, and the side-blow air stream increasingly suppresses the plasma. It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action. Therefore, the side-blown airflow alone cannot completely clear the plasma. Depending on the delay conditions, the pressure of the side-blowing airflow and the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as double combustion wave when using a nanosecond pulse laser. Both simulation and experimental results are consistent, indicating the potential for further exploration of fused silica targets in the laser field.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"18 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140775072","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}
Pub Date : 2024-04-01DOI: 10.1088/2058-6272/ad3952
Domen Paul, M. Mozetič, R. Zaplotnik, A. Vesel, G. Primc, D. Đonlagič
Catalysis of molecular radicals is often performed in interesting experimental configurations. One possible configuration is tubular geometry. The radicals are introduced into the tubes on one side, and stable molecules are exhausted on the other side. The penetration depth of radicals depends on numerous parameters, so it is not always feasible to calculate it. This article presents systematic measurements of the penetration depth of oxygen atoms along tubes made from nickel, cobalt, and copper. The source of O atoms was a surfatron-type microwave plasma. The initial density of O atoms depended on the gas flow and was 0.7, 2.4, and 4.2 〖∙10〗^21 m^(-3) at the flow rates of 50, 300, and 600 sccm, and pressure of 10, 35, and 60 Pa, respectively. The gas temperature remained at room temperature throughout the experiments. The dissociation fraction decreased exponentially along the length of the tubes in all cases. The penetration depths for well-oxidized nickel were 1.2, 1.7, and 2.4 cm, respectively. For cobalt, they were slightly lower at 1.0, 1.3, and 1.6 cm, respectively, while for copper, they were 1.1, 1.3, and 1.7 cm, respectively. The results were explained by gas dynamics and heterogeneous surface association. These data are useful in any attempt to estimate the loss of molecular fragments along tubes, which serve as catalysts for the association of various radicals to stable molecules.
{"title":"The penetration depth of atomic radicals in tubes with catalytic surface properties","authors":"Domen Paul, M. Mozetič, R. Zaplotnik, A. Vesel, G. Primc, D. Đonlagič","doi":"10.1088/2058-6272/ad3952","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3952","url":null,"abstract":"\u0000 Catalysis of molecular radicals is often performed in interesting experimental configurations. One possible configuration is tubular geometry. The radicals are introduced into the tubes on one side, and stable molecules are exhausted on the other side. The penetration depth of radicals depends on numerous parameters, so it is not always feasible to calculate it. This article presents systematic measurements of the penetration depth of oxygen atoms along tubes made from nickel, cobalt, and copper. The source of O atoms was a surfatron-type microwave plasma. The initial density of O atoms depended on the gas flow and was 0.7, 2.4, and 4.2 〖∙10〗^21 m^(-3) at the flow rates of 50, 300, and 600 sccm, and pressure of 10, 35, and 60 Pa, respectively. The gas temperature remained at room temperature throughout the experiments. The dissociation fraction decreased exponentially along the length of the tubes in all cases. The penetration depths for well-oxidized nickel were 1.2, 1.7, and 2.4 cm, respectively. For cobalt, they were slightly lower at 1.0, 1.3, and 1.6 cm, respectively, while for copper, they were 1.1, 1.3, and 1.7 cm, respectively. The results were explained by gas dynamics and heterogeneous surface association. These data are useful in any attempt to estimate the loss of molecular fragments along tubes, which serve as catalysts for the association of various radicals to stable molecules.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"169 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140790585","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}
In this work, a bright and dark concentric-ring pattern is reported in the dielectric barrier discharge for the first time. The spatiotemporal dynamics of the bright and dark concentric-ring pattern is investigated by an intensified charge-coupled device and photomultiplier tubes. The results indicate that the bright and dark concentric-ring pattern is composed of three concentric-ring sub-lattices. They are bright concentric-ring structures, dark concentric-ring structures and wider concentric-ring structures, respectively. The bright concentric-ring structures and dark concentric-ring structures are alternately distributed. The bright concentric-ring structures are located at the centre of the wider concentric-ring structures. The formation of the wider concentric-ring structures is first formed from the outer edge and gradually develops to the centre. The essence of all three concentric-ring structures is the individual discharge filaments. The optical emission spectra of different sub-lattices are acquired and analyzed. It is found that the plasma parameters of the three concentric-ring sub-lattices are different. Finally, the formation mechanism of the bright and dark concentric-ring pattern is discussed.
{"title":"Formation mechanism of bright and dark concentric-ring pattern in dielectric barrier discharge","authors":"Caixia Li, Jian-yu Feng, Shuchang Wang, Cheng Li, Junxia Ran, Yuyang Pan, Lifang Dong","doi":"10.1088/2058-6272/ad386a","DOIUrl":"https://doi.org/10.1088/2058-6272/ad386a","url":null,"abstract":"\u0000 In this work, a bright and dark concentric-ring pattern is reported in the dielectric barrier discharge for the first time. The spatiotemporal dynamics of the bright and dark concentric-ring pattern is investigated by an intensified charge-coupled device and photomultiplier tubes. The results indicate that the bright and dark concentric-ring pattern is composed of three concentric-ring sub-lattices. They are bright concentric-ring structures, dark concentric-ring structures and wider concentric-ring structures, respectively. The bright concentric-ring structures and dark concentric-ring structures are alternately distributed. The bright concentric-ring structures are located at the centre of the wider concentric-ring structures. The formation of the wider concentric-ring structures is first formed from the outer edge and gradually develops to the centre. The essence of all three concentric-ring structures is the individual discharge filaments. The optical emission spectra of different sub-lattices are acquired and analyzed. It is found that the plasma parameters of the three concentric-ring sub-lattices are different. Finally, the formation mechanism of the bright and dark concentric-ring pattern is discussed.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"11 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140377247","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}
Pub Date : 2024-03-27DOI: 10.1088/2058-6272/ad386b
Zhicheng Jiao, D. Dai, rui Ming Zhu, Tao Shao, Buang Wang
Secondary electron emission (SEE) induced by the positive ion is an essential physical process to influence the dynamics of gas discharge which relies on the specific surface material. Surface charging has a significant impact on the material properties, thereby affecting the SEE in the plasma-surface interactions. However, it does not attract enough attention in the previous studies. In this paper, SEE dependent on the charged surface of specific materials is described with the computational method combining a density functional theory (DFT) model from the first-principle theory and the theory of Auger neutralization. The effect of κ-Al2O3 surface charge, as an example, on the ion-induced secondary electron emission coefficient (SEEC) is investigated by analysing the defect energy level and band structure on the charged surface. Simulation results indicate that, with the surface charge from negative to positive, the SEEC of a part of low ionization energy ions (such as Ei = 12.6 eV) increases first and then decreases, exhibiting a nonlinear changing trend. This is quite different from the monotonic decreasing tendency observed in the previous model which simplifies the electronic structure. This irregular increase of the SEEC can be attributed to the lower escaped probability of orbital energy. The results further illustrate that the excessive charge could cause the bottom of the conduction band close to the valence band, thus leading to the decrease of the orbital energy occupied by the excited electrons. The nonlinear change of SEEC demonstrates a more realistic situation of how the electronic structure of material surface influences the SEE process. This work provides an accurate method of calculating SEEC from specific materials, which is urgent in widespread physical scenarios sensitive to surface materials, such as increasingly growing practical applications concerning plasma-surface interactions.
正离子诱导的二次电子发射（SEE）是影响气体放电动力学的一个重要物理过程，它依赖于特定的表面材料。表面充电对材料特性有重大影响，从而影响等离子体与表面相互作用中的 SEE。然而，在以往的研究中，这一问题并没有引起足够的重视。本文结合第一原理理论中的密度泛函理论（DFT）模型和欧杰中和理论，通过计算方法描述了特定材料带电表面对 SEE 的影响。以κ-Al2O3 表面电荷为例，通过分析带电表面的缺陷能级和能带结构，研究了离子诱导的二次电子发射系数（SEEC）的影响。模拟结果表明，随着表面电荷由负转正，部分低电离能离子（如 Ei = 12.6 eV）的二次电子发射系数先增大后减小，呈现非线性变化趋势。这与之前简化电子结构的模型中观察到的单调递减趋势截然不同。SEEC 的这种不规则增加可归因于轨道能量的逸散概率较低。结果进一步说明，过多的电荷可能导致导带底部接近价带，从而导致受激电子占据的轨道能量减少。SEEC 的非线性变化展示了材料表面电子结构如何影响 SEE 过程的更真实情况。这项工作提供了一种计算特定材料 SEEC 的精确方法，这在对表面材料敏感的广泛物理场景中非常迫切，例如日益增多的有关等离子体与表面相互作用的实际应用。
{"title":"Nonlinear change of ion-induced secondary electron emission in the κ-Al2O3 surface charging from first-principle modelling","authors":"Zhicheng Jiao, D. Dai, rui Ming Zhu, Tao Shao, Buang Wang","doi":"10.1088/2058-6272/ad386b","DOIUrl":"https://doi.org/10.1088/2058-6272/ad386b","url":null,"abstract":"\u0000 Secondary electron emission (SEE) induced by the positive ion is an essential physical process to influence the dynamics of gas discharge which relies on the specific surface material. Surface charging has a significant impact on the material properties, thereby affecting the SEE in the plasma-surface interactions. However, it does not attract enough attention in the previous studies. In this paper, SEE dependent on the charged surface of specific materials is described with the computational method combining a density functional theory (DFT) model from the first-principle theory and the theory of Auger neutralization. The effect of κ-Al2O3 surface charge, as an example, on the ion-induced secondary electron emission coefficient (SEEC) is investigated by analysing the defect energy level and band structure on the charged surface. Simulation results indicate that, with the surface charge from negative to positive, the SEEC of a part of low ionization energy ions (such as Ei = 12.6 eV) increases first and then decreases, exhibiting a nonlinear changing trend. This is quite different from the monotonic decreasing tendency observed in the previous model which simplifies the electronic structure. This irregular increase of the SEEC can be attributed to the lower escaped probability of orbital energy. The results further illustrate that the excessive charge could cause the bottom of the conduction band close to the valence band, thus leading to the decrease of the orbital energy occupied by the excited electrons. The nonlinear change of SEEC demonstrates a more realistic situation of how the electronic structure of material surface influences the SEE process. This work provides an accurate method of calculating SEEC from specific materials, which is urgent in widespread physical scenarios sensitive to surface materials, such as increasingly growing practical applications concerning plasma-surface interactions.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"10 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140374305","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}
Pub Date : 2024-03-22DOI: 10.1088/2058-6272/ad370b
S. Elashry, U. Rashed, Mostafa Wahba, Hend Ahmed, Nabil El-Siragy
This paper discusses the use of atmospheric pressure dielectric barrier discharge (DBD) plasma treatment to enhance the surface qualities of viscose fabrics. The study explores the effects of different plasma gases, discharge voltages, and exposure times on the treated fabrics. The findings emphasize the importance of optimizing the plasma's peak voltage to achieve desired surface treatment outcomes. The document also presents data on color strength, wettability, color fastness, and tensile strength of the treated fabrics, as well as SEM analysis of surface morphology and chemical analysis using FTIR and EDX. The results show that treatment at a peak voltage of 11.83 kV is more efficient, except for the tensile strength which is enhanced at a peak voltage of 8.92 kV. The oxygen plasma treatment significantly improves the color strength, which exhibits an increase from 11 to 18. The intensified color was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules, which enhance the printability. The oxygen dielectric barrier discharge plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas. This study presents a sustainable, economical, secure, and ecologically friendly approach to explore new fabrics for specific uses.
{"title":"Surface activation of viscose textiles via air, argon, and oxygen dielectric barrier discharge plasma: Influence of peak voltage","authors":"S. Elashry, U. Rashed, Mostafa Wahba, Hend Ahmed, Nabil El-Siragy","doi":"10.1088/2058-6272/ad370b","DOIUrl":"https://doi.org/10.1088/2058-6272/ad370b","url":null,"abstract":"\u0000 This paper discusses the use of atmospheric pressure dielectric barrier discharge (DBD) plasma treatment to enhance the surface qualities of viscose fabrics. The study explores the effects of different plasma gases, discharge voltages, and exposure times on the treated fabrics. The findings emphasize the importance of optimizing the plasma's peak voltage to achieve desired surface treatment outcomes. The document also presents data on color strength, wettability, color fastness, and tensile strength of the treated fabrics, as well as SEM analysis of surface morphology and chemical analysis using FTIR and EDX. The results show that treatment at a peak voltage of 11.83 kV is more efficient, except for the tensile strength which is enhanced at a peak voltage of 8.92 kV. The oxygen plasma treatment significantly improves the color strength, which exhibits an increase from 11 to 18. The intensified color was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules, which enhance the printability. The oxygen dielectric barrier discharge plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas. This study presents a sustainable, economical, secure, and ecologically friendly approach to explore new fabrics for specific uses.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":" 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140216098","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}
Pub Date : 2024-03-22DOI: 10.1088/2058-6272/ad370c
Yihan Lv, Wei-xi Song, Z. Hou, Zhe Wang
Nowadays, laser-induced breakdown spectroscopy (LIBS) has become a widely used atomic spectroscopic technique for rapid coal analysis. While the vast spectral information in LIBS contains signal uncertainty, which can impact its quantification performance. In this work, we proposed a hybrid variable selection method to improve the performance of LIBS quantification. Important variables are first identified using Pearson’s correlation coefficient (PCC), mutual information (MI), least absolute shrinkage and selection operator (LASSO) and random forest (RF), and then filtered and combined with empirical variables related to fingerprint elements of coal ash content. Subsequently, these variables are fed into partial least squares regression (PLSR). Additionally, in some models, certain variables unrelated to ash content were removed manually to study the variable deselection’s impact on model performance. The proposed hybrid strategy was tested on three LIBS datasets for quantitative analysis of coal ash content and compared with the corresponding data-driven baseline method. It is significantly better than the variable selection only based on empirical knowledge and in most cases outperforms the baseline method. The results showed that on all three datasets, hybrid strategy for variable selection combining empirical knowledge and data-driven algorithms achieved the lowest RMSEP values of 1.605, 3.478 and 1.647, respectively, which were significantly lower than those obtained from multiple linear regression using only 12 empirical variables, which are 1.959, 3.718 and 2.181, respectively. The EMP-LASSO-PLSR model with 20 selected variables exhibited a significant improving performance after variable deselection, with RMSEP values dropping from 1.635, 3.962, 1.647 to 1.483, 3.086, 1.567, respectively. Such results demonstrate that using empirical knowledge as a support to data-driven variable selection can be a viable approach to improve the accuracy and reliability of LIBS quantification.
{"title":"Incorporating empirical knowledge into data-driven variable selection for quantitative analysis of coal ash content by laser-induced breakdown spectroscopy","authors":"Yihan Lv, Wei-xi Song, Z. Hou, Zhe Wang","doi":"10.1088/2058-6272/ad370c","DOIUrl":"https://doi.org/10.1088/2058-6272/ad370c","url":null,"abstract":"\u0000 Nowadays, laser-induced breakdown spectroscopy (LIBS) has become a widely used atomic spectroscopic technique for rapid coal analysis. While the vast spectral information in LIBS contains signal uncertainty, which can impact its quantification performance. In this work, we proposed a hybrid variable selection method to improve the performance of LIBS quantification. Important variables are first identified using Pearson’s correlation coefficient (PCC), mutual information (MI), least absolute shrinkage and selection operator (LASSO) and random forest (RF), and then filtered and combined with empirical variables related to fingerprint elements of coal ash content. Subsequently, these variables are fed into partial least squares regression (PLSR). Additionally, in some models, certain variables unrelated to ash content were removed manually to study the variable deselection’s impact on model performance. The proposed hybrid strategy was tested on three LIBS datasets for quantitative analysis of coal ash content and compared with the corresponding data-driven baseline method. It is significantly better than the variable selection only based on empirical knowledge and in most cases outperforms the baseline method. The results showed that on all three datasets, hybrid strategy for variable selection combining empirical knowledge and data-driven algorithms achieved the lowest RMSEP values of 1.605, 3.478 and 1.647, respectively, which were significantly lower than those obtained from multiple linear regression using only 12 empirical variables, which are 1.959, 3.718 and 2.181, respectively. The EMP-LASSO-PLSR model with 20 selected variables exhibited a significant improving performance after variable deselection, with RMSEP values dropping from 1.635, 3.962, 1.647 to 1.483, 3.086, 1.567, respectively. Such results demonstrate that using empirical knowledge as a support to data-driven variable selection can be a viable approach to improve the accuracy and reliability of LIBS quantification.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":" 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140218929","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}
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