Pub Date : 2024-03-21DOI: 10.1088/2058-6272/ad36aa
Qi Dong, Jie Zhang, Tao Lan, C. Xiao, Zhuang Ge, Chen Chen, Yongkang Zhou, Jie Wu, T. Long, Lin Nie, Pengcheng Lu, Tianxiong Wang, Jiaren Wu, Peng Deng, Xingkang Wang, Zeqi Bai, Yuhua Huang, Jie Li, Lie Xue, Yolbarsop Adil, W. Mao, Chu Zhou, A. Liu, Zhengwei Wu, Jinlin Xie, Weixing Ding, Wandong Liu, Wei Chen, Wulyu Zhong, Min Xu, Xuru Duan
The trajectory of the compact torus (CT) within a tokamak discharge is crucial to fueling. In this study, we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges. This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks. For perpendicular injection along the tokamak's major radius direction from the outboard, CTs with the same injection parameters exhibited an 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13 reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered. In addition, we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks. Furthermore, this paper discusses schemes for the tangential injection of CT into tokamak discharges. The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations. Finally, the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced by ΔEk=975.08J by optimizing the injection angle for the CT injected into ITER. These results provided valuable insights for optimizing injection angles in fusion experiments. Our model closely represents actual experimental scenarios and can assist the design of CT parameters.
{"title":"Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma","authors":"Qi Dong, Jie Zhang, Tao Lan, C. Xiao, Zhuang Ge, Chen Chen, Yongkang Zhou, Jie Wu, T. Long, Lin Nie, Pengcheng Lu, Tianxiong Wang, Jiaren Wu, Peng Deng, Xingkang Wang, Zeqi Bai, Yuhua Huang, Jie Li, Lie Xue, Yolbarsop Adil, W. Mao, Chu Zhou, A. Liu, Zhengwei Wu, Jinlin Xie, Weixing Ding, Wandong Liu, Wei Chen, Wulyu Zhong, Min Xu, Xuru Duan","doi":"10.1088/2058-6272/ad36aa","DOIUrl":"https://doi.org/10.1088/2058-6272/ad36aa","url":null,"abstract":"\u0000 The trajectory of the compact torus (CT) within a tokamak discharge is crucial to fueling. In this study, we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges. This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks. For perpendicular injection along the tokamak's major radius direction from the outboard, CTs with the same injection parameters exhibited an 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13 reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered. In addition, we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks. Furthermore, this paper discusses schemes for the tangential injection of CT into tokamak discharges. The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations. Finally, the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced by ΔEk=975.08J by optimizing the injection angle for the CT injected into ITER. These results provided valuable insights for optimizing injection angles in fusion experiments. Our model closely represents actual experimental scenarios and can assist the design of CT parameters.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"56 s197","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140223383","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}
Stabilization of tearing modes and neoclassical tearing modes is of great importance for the tokamak operation. Electron cyclotron wave (ECW) has been extensively used to stabilize the tearing modes with the virtue of the highly localized power deposition. Complete suppression of the m/n = 2/1 tearing mode (TM) by electron cyclotron resonance heating (ECRH) has been achieved successfully on the J-TEXT tokamak. The effect of ECW deposition location and power amplitude on the 2/1 TM suppression have been investigated. It is found that the suppression is more effective when the ECW power is deposited closer to the rational surface. Partial suppression of the 2/1 TM by ECRH has been observed and the island width is reduced by 65% of the initial island width. The island rotation frequency is increased when the island width is reduced. The experimental results show that the temperature perturbations increase inside the magnetic island produced by the local heating plays a dominant role on tearing modes suppression. As the ECW power increased, the 2/1 island is suppressed to smaller islands width and the flow shear also plays a stabilizing effect on small magnetic islands. With the stabilizing contribution of heating and the flow shear, the 2/1 TM can be completely suppressed.
{"title":"Suppression of the m/n = 2/1 tearing mode by electron cyclotron resonance heating on J-TEXT","authors":"Fang Jian Gang, Z. Chen, W. Yan, Nengchao Wang, Feiyue Mao, Qiang Luo, Zijian Xuan, Xixuan Chen, Zhengkang Ren, Feng Zhang, Mei Huang, Donghui Xia, Zhoujun Yang, Zhipeng Chen, Yonghua Ding","doi":"10.1088/2058-6272/ad3616","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3616","url":null,"abstract":"\u0000 Stabilization of tearing modes and neoclassical tearing modes is of great importance for the tokamak operation. Electron cyclotron wave (ECW) has been extensively used to stabilize the tearing modes with the virtue of the highly localized power deposition. Complete suppression of the m/n = 2/1 tearing mode (TM) by electron cyclotron resonance heating (ECRH) has been achieved successfully on the J-TEXT tokamak. The effect of ECW deposition location and power amplitude on the 2/1 TM suppression have been investigated. It is found that the suppression is more effective when the ECW power is deposited closer to the rational surface. Partial suppression of the 2/1 TM by ECRH has been observed and the island width is reduced by 65% of the initial island width. The island rotation frequency is increased when the island width is reduced. The experimental results show that the temperature perturbations increase inside the magnetic island produced by the local heating plays a dominant role on tearing modes suppression. As the ECW power increased, the 2/1 island is suppressed to smaller islands width and the flow shear also plays a stabilizing effect on small magnetic islands. With the stabilizing contribution of heating and the flow shear, the 2/1 TM can be completely suppressed.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"9 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140226626","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 : 2024-03-20DOI: 10.1088/2058-6272/ad3615
L. Torrisi, L. Silipigni, Alfio Torrisi, M. Cutroneo
MoS2 targets were irradiated by Infra-Red (IR) pulsed laser in a high vacuum to determine hot plasma parameters, atomic, molecular and ion emission, and angular and charge state distributions. In this way, pulsed laser deposition (PLD) of thin films on graphene oxide substrates was also realized. A Nd:YAG laser, operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy, in a single pulse or at a 10 Hz repetition rate, was employed. Ablation yield was measured as a function of the laser fluence. Plasma was characterized using different analysis techniques, such as time-of-flight measurements, quadrupole mass spectrometry and fast CCD visible imaging. The so-produced films were characterized by composition, thickness, roughness, wetting ability, and morphology. When compared to the MoS2 targets, they show a slight decrease of S with respect to Mo, due to higher ablation yield, low fusion temperature and high sublimation in vacuum. The pulsed IR laser deposited MoSx (with 1 < x < 2) films are uniform, with a thickness of about 130 nm, a roughness of about 50 nm and a higher wettability than the MoS2 targets. Some potential applications of the pulsed IR laser-deposited MoSx films are also presented and discussed.
{"title":"Investigations on MoS2 plasma by IR pulsed laser irradiation in high vacuum","authors":"L. Torrisi, L. Silipigni, Alfio Torrisi, M. Cutroneo","doi":"10.1088/2058-6272/ad3615","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3615","url":null,"abstract":"\u0000 MoS2 targets were irradiated by Infra-Red (IR) pulsed laser in a high vacuum to determine hot plasma parameters, atomic, molecular and ion emission, and angular and charge state distributions. In this way, pulsed laser deposition (PLD) of thin films on graphene oxide substrates was also realized. A Nd:YAG laser, operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy, in a single pulse or at a 10 Hz repetition rate, was employed. Ablation yield was measured as a function of the laser fluence. Plasma was characterized using different analysis techniques, such as time-of-flight measurements, quadrupole mass spectrometry and fast CCD visible imaging. The so-produced films were characterized by composition, thickness, roughness, wetting ability, and morphology. When compared to the MoS2 targets, they show a slight decrease of S with respect to Mo, due to higher ablation yield, low fusion temperature and high sublimation in vacuum. The pulsed IR laser deposited MoSx (with 1 < x < 2) films are uniform, with a thickness of about 130 nm, a roughness of about 50 nm and a higher wettability than the MoS2 targets. Some potential applications of the pulsed IR laser-deposited MoSx films are also presented and discussed.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140227519","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 : 2024-03-19DOI: 10.1088/2058-6272/ad3599
Maoyang Li, Chaochao Mo, Jiali Chen, P. Ji, Haiyun Tan, Xiaoman Zhang, Meili Cui, L. Zhuge, Xuemei Wu, Tianyuan Huang
This study delves into ion behavior at the substrate position within RF magnetron discharges utilizing an indium tin oxide (ITO) target. The positive ion energies exhibit an upward trajectory with increasing RF power, attributed to heightened plasma potential and initial emergent energy. Simultaneously, the positive ion flux escalates owing to amplified sputtering rates and electron density. Conversely, negative ions exhibit broad ion energy distribution functions (IEDFs) characterized by multiple peaks. These patterns are clarified by a combination of radiofrequency oscillation of cathode voltage and plasma potential, alongside ion transport time. This elucidation finds validation in a one-dimensional model encompassing the initial ion energy. At higher RF power, negative ions surpassing 100 eV escalate in both flux and energy, posing a potential risk of sputtering damages to ITO layers.
本研究深入探讨了利用铟锡氧化物（ITO）靶的射频磁控管放电中基片位置的离子行为。正离子能量随着射频功率的增加而呈现上升轨迹，这归因于等离子体势能和初始出现能量的增加。与此同时，由于溅射率和电子密度的提高，正离子流量也随之增加。相反，负离子则表现出以多峰为特征的宽离子能量分布函数（IEDF）。通过结合阴极电压和等离子体电位的射频振荡以及离子传输时间，这些模式得到了澄清。这一解释在包含初始离子能量的一维模型中得到了验证。在较高的射频功率下，超过 100 eV 的负离子流量和能量都会增加，从而对 ITO 层造成潜在的溅射损坏风险。
{"title":"Effects of power on ion behaviors in radio-frequency magnetron sputtering of indium tin oxide (ITO)","authors":"Maoyang Li, Chaochao Mo, Jiali Chen, P. Ji, Haiyun Tan, Xiaoman Zhang, Meili Cui, L. Zhuge, Xuemei Wu, Tianyuan Huang","doi":"10.1088/2058-6272/ad3599","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3599","url":null,"abstract":"\u0000 This study delves into ion behavior at the substrate position within RF magnetron discharges utilizing an indium tin oxide (ITO) target. The positive ion energies exhibit an upward trajectory with increasing RF power, attributed to heightened plasma potential and initial emergent energy. Simultaneously, the positive ion flux escalates owing to amplified sputtering rates and electron density. Conversely, negative ions exhibit broad ion energy distribution functions (IEDFs) characterized by multiple peaks. These patterns are clarified by a combination of radiofrequency oscillation of cathode voltage and plasma potential, alongside ion transport time. This elucidation finds validation in a one-dimensional model encompassing the initial ion energy. At higher RF power, negative ions surpassing 100 eV escalate in both flux and energy, posing a potential risk of sputtering damages to ITO layers.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"6 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140230492","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 : 2024-03-17DOI: 10.1088/2058-6272/ad34ba
Min Yang, Kaixuan Qi, Jiuwen Yang, Sa Jia, Haoyan Liu, Yanyang Chen, Jin Li, Xiaoping Li
During spacecraft re-entry, the challenge of measuring plasma sheath parameters directly contributes to difficulties in addressing communication blackout. In this work, we have discovered a phenomenon of multiple peaks in reflection data caused by the inhomogeneous plasma. Simulation results show that the multi-peak points fade away as the characteristic frequency is approached, resembling a series of gradually decreasing peaks. The positions and quantities of these points are positively correlated with electron density, yet they show no relation to collision frequency. This phenomenon is of significant reference value for future studies on the spatial distribution of plasmas, particularly for using microwave reflection signals in diagnosing the plasma sheath.
{"title":"The multi-peak point phenomenon of broadband microwave reflection caused by inhomogeneous plasma","authors":"Min Yang, Kaixuan Qi, Jiuwen Yang, Sa Jia, Haoyan Liu, Yanyang Chen, Jin Li, Xiaoping Li","doi":"10.1088/2058-6272/ad34ba","DOIUrl":"https://doi.org/10.1088/2058-6272/ad34ba","url":null,"abstract":"\u0000 During spacecraft re-entry, the challenge of measuring plasma sheath parameters directly contributes to difficulties in addressing communication blackout. In this work, we have discovered a phenomenon of multiple peaks in reflection data caused by the inhomogeneous plasma. Simulation results show that the multi-peak points fade away as the characteristic frequency is approached, resembling a series of gradually decreasing peaks. The positions and quantities of these points are positively correlated with electron density, yet they show no relation to collision frequency. This phenomenon is of significant reference value for future studies on the spatial distribution of plasmas, particularly for using microwave reflection signals in diagnosing the plasma sheath.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"7 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140235198","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 : 2024-03-16DOI: 10.1088/2058-6272/ad34aa
V. Tarasenko, D. Beloplotov, Panchenko Alexey, Dmitry Sorokin
The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay. Positive and negative nanosecond voltage pulses with an amplitude of tens kV were applied. Time-resolved images of the discharge development were taken with a four-channel ICCD camera. The minimum delay between the camera channels could be as short as 0.1 ns. This made it possible to study the gap breakdown process with subnanosecond resolution. It was observed that a wide-diameter streamer develops from the high-voltage pointed electrode. The ionization processes near the grounded pin electrode started when the streamer crossed half of the gap. After bridging the gap by the streamer, a diffuse discharge was formed. The development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next stage. It was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter streamer. Long thin luminous tracks were observed against the background of a discharge plasma glow. It has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.
{"title":"Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles","authors":"V. Tarasenko, D. Beloplotov, Panchenko Alexey, Dmitry Sorokin","doi":"10.1088/2058-6272/ad34aa","DOIUrl":"https://doi.org/10.1088/2058-6272/ad34aa","url":null,"abstract":"\u0000 The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay. Positive and negative nanosecond voltage pulses with an amplitude of tens kV were applied. Time-resolved images of the discharge development were taken with a four-channel ICCD camera. The minimum delay between the camera channels could be as short as 0.1 ns. This made it possible to study the gap breakdown process with subnanosecond resolution. It was observed that a wide-diameter streamer develops from the high-voltage pointed electrode. The ionization processes near the grounded pin electrode started when the streamer crossed half of the gap. After bridging the gap by the streamer, a diffuse discharge was formed. The development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next stage. It was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter streamer. Long thin luminous tracks were observed against the background of a discharge plasma glow. It has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"95 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140236604","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 : 2024-03-15DOI: 10.1088/2058-6272/ad3499
T. Habib, J. A. M. Caiut, Bruno Caillier
Homogeneous gold nanoparticles were synthesized under atmospheric pressure using a non-thermal helium plasma jet in a single-step process. A current power supply was used to generate the plasma discharge rich in diverse reactive species. These species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid solution. In this study, spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing Gold (III) chloride hydrate (HAuCl4) as a precursor and Polyvinylpyrrolidone (PVP) as a capping agent to inhibit agglomerations. The formation of these metal nanoparticles was initially perceptible through a visible change in the sample’s color, transitioning from light yellow to a red/pink color. This was subsequently corroborated by UV-vis spectroscopy, which revealed an optical absorption in the 520 - 550 nm range for AuNPs, corresponding to the surface plasmon resonance (SPR) band. An investigation into the impact of various parameters, including plasma discharge duration, precursor and capping agent concentrations, was carried out to optimize conditions for the formation of well-separated, spherical gold nanoparticles. Dynamic light scattering (DLS) was used to measure the size of these nanoparticles, transmission electron microscopy (TEM) was used to observe their morphology and X-ray diffraction (XRD) was also employed to determine their crystallographic structure. The results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid, straightforward, and environmentally friendly approach utilizing a helium atmospheric pressure plasma.
{"title":"Fast synthesis of gold nanoparticles by cold atmospheric pressure plasma jet in the presence of Au+ ions and a capping agent","authors":"T. Habib, J. A. M. Caiut, Bruno Caillier","doi":"10.1088/2058-6272/ad3499","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3499","url":null,"abstract":"\u0000 Homogeneous gold nanoparticles were synthesized under atmospheric pressure using a non-thermal helium plasma jet in a single-step process. A current power supply was used to generate the plasma discharge rich in diverse reactive species. These species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid solution. In this study, spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing Gold (III) chloride hydrate (HAuCl4) as a precursor and Polyvinylpyrrolidone (PVP) as a capping agent to inhibit agglomerations. The formation of these metal nanoparticles was initially perceptible through a visible change in the sample’s color, transitioning from light yellow to a red/pink color. This was subsequently corroborated by UV-vis spectroscopy, which revealed an optical absorption in the 520 - 550 nm range for AuNPs, corresponding to the surface plasmon resonance (SPR) band. An investigation into the impact of various parameters, including plasma discharge duration, precursor and capping agent concentrations, was carried out to optimize conditions for the formation of well-separated, spherical gold nanoparticles. Dynamic light scattering (DLS) was used to measure the size of these nanoparticles, transmission electron microscopy (TEM) was used to observe their morphology and X-ray diffraction (XRD) was also employed to determine their crystallographic structure. The results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid, straightforward, and environmentally friendly approach utilizing a helium atmospheric pressure plasma.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140241251","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}
Archimedean photonic crystal has become a research area of great interest due to its various unique properties. Here, we experimentally demonstrate the realization of reconfigurable (4, 6²) and (4, 8²) Archimedean plasma photonic crystals (APPCs) by the use of dielectric barrier discharges in air. Dynamical control on both the macrostructures including the lattice symmetry and the crystal orientation, and the microstructures including the fine structures of scattering elements has been achieved. The formation mechanisms of APPCs are studied by time-resolved measurements together with numerical simulations. Large omnidirectional band gaps of APPCs have been obtained. The tunable topology of APPCs may offer new opportunities for fabricating multi-functional and highly-integrated microwave devices.
{"title":"Reconfigurable (4, 6²) and (4, 8²) Archimedean Plasma Photonic Crystals in Dielectric Barrier Discharge","authors":"Rui Li, Qi-han Wang, Fucheng Liu, Kuangya Gao, Xiaohan Hou, Mengmeng Jia, Qing Li, Weili Fan","doi":"10.1088/2058-6272/ad341f","DOIUrl":"https://doi.org/10.1088/2058-6272/ad341f","url":null,"abstract":"\u0000 Archimedean photonic crystal has become a research area of great interest due to its various unique properties. Here, we experimentally demonstrate the realization of reconfigurable (4, 6²) and (4, 8²) Archimedean plasma photonic crystals (APPCs) by the use of dielectric barrier discharges in air. Dynamical control on both the macrostructures including the lattice symmetry and the crystal orientation, and the microstructures including the fine structures of scattering elements has been achieved. The formation mechanisms of APPCs are studied by time-resolved measurements together with numerical simulations. Large omnidirectional band gaps of APPCs have been obtained. The tunable topology of APPCs may offer new opportunities for fabricating multi-functional and highly-integrated microwave devices.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"11 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140241491","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 : 2024-03-14DOI: 10.1088/2058-6272/ad3420
Qingyun Lei, Xiong Yang, M. Cheng, Fan Zhang, D. Guo, Xiaokang Li, Wenjie Xiao
Laser-induced fluorescence (LIF) spectroscopy is employed for plasma diagnosis, necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal. However, direct deconvolution becomes invalid in the presence of noise as it leads to infinite amplification of high-frequency noise components. To address this issue, we propose a deconvolution algorithm based on the maximum entropy principle. We validate the effectiveness of the proposed algorithm by utilizing simulated LIF spectra at various noise levels (signal-to-noise ratio, SNR = 20–80 dB) and measured LIF spectra with Xe as the working fluid. In the typical measured spectrum (SNR = 26.23 dB) experiment, compared with the Gaussian filter and the Richardson-Lucy (R-L) algorithm, the proposed algorithm demonstrates an increase in SNR by 1.39 dB and 4.66 dB respectively, along with a reduction in root-mean-square error (RMSE) by 35% and 64% respectively. Additionally, there is a decrease in spectral angle (SA) by 0.05 and 0.11 respectively. In the high quality spectrum (SNR = 43.96 dB) experiment, the results show that the running time of the proposed algorithm is reduced by about 98% compared with the R-L iterative algorithm. Moreover, the maximum entropy algorithm avoids parameter optimization settings and is more suitable for automatic implementation. In conclusion, the proposed algorithm can accurately resolve Doppler spectrum details while effectively suppressing noise, thus highlighting its advantage in LIF spectral deconvolution applications.
{"title":"Research on the deconvolution algorithm for the laser-induced fluorescence diagnosis based on the maximum entropy principle","authors":"Qingyun Lei, Xiong Yang, M. Cheng, Fan Zhang, D. Guo, Xiaokang Li, Wenjie Xiao","doi":"10.1088/2058-6272/ad3420","DOIUrl":"https://doi.org/10.1088/2058-6272/ad3420","url":null,"abstract":"\u0000 Laser-induced fluorescence (LIF) spectroscopy is employed for plasma diagnosis, necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal. However, direct deconvolution becomes invalid in the presence of noise as it leads to infinite amplification of high-frequency noise components. To address this issue, we propose a deconvolution algorithm based on the maximum entropy principle. We validate the effectiveness of the proposed algorithm by utilizing simulated LIF spectra at various noise levels (signal-to-noise ratio, SNR = 20–80 dB) and measured LIF spectra with Xe as the working fluid. In the typical measured spectrum (SNR = 26.23 dB) experiment, compared with the Gaussian filter and the Richardson-Lucy (R-L) algorithm, the proposed algorithm demonstrates an increase in SNR by 1.39 dB and 4.66 dB respectively, along with a reduction in root-mean-square error (RMSE) by 35% and 64% respectively. Additionally, there is a decrease in spectral angle (SA) by 0.05 and 0.11 respectively. In the high quality spectrum (SNR = 43.96 dB) experiment, the results show that the running time of the proposed algorithm is reduced by about 98% compared with the R-L iterative algorithm. Moreover, the maximum entropy algorithm avoids parameter optimization settings and is more suitable for automatic implementation. In conclusion, the proposed algorithm can accurately resolve Doppler spectrum details while effectively suppressing noise, thus highlighting its advantage in LIF spectral deconvolution applications.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"66 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140242403","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 : 2024-03-11DOI: 10.1088/2058-6272/ad3286
Rui Tan, Guanrong Hang, Pingyang Wang
Magnetic field design is essential for the operation of Hall thrusters. This study focuses on utilizing a genetic algorithm to optimize the magnetic field configuration of SPT70. A 2D hybrid PIC-DSMC and channel-wall erosion model are employed to analyze the plume divergence angle and wall erosion rate, while a Farady probe measurement and laser profilometry system are set up to verify the simulation results. The results demonstrate that the genetic algorithm contributes to reducing the divergence angle of the thruster plumes and alleviating the impact of high-energy particles on the discharge channel wall，reducing the erosion by 5.5% and 2.7%, respectively. Further analysis indicates that the change from a divergent magnetic field to a convergent magnetic field, combined with the upstream shift of the ionization region, contributes to the improving the operation of the Hall thruster.
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