Plasma Science and Technology最新文献

{"title":"Tunable topological edge state in plasma photonic crystals","authors":"Mingjie Zhou, Haiyun Tan, L. Zhuge, Xuemei Wu","doi":"10.1088/2058-6272/ad62d5","DOIUrl":"https://doi.org/10.1088/2058-6272/ad62d5","url":null,"abstract":"\u0000 In this work, we found a kind of edge state located at the interface between plasma photonic crystals (PPCs) and traditional photonic crystals, which depends on the property of the photonic band gap rather than the surface defect. Simulation and theoretical analysis show that by adjusting plasma density, we can change the topological characteristics of the photonic bandgap of PPCs, making it different from the photonic bandgap of traditional PCs, and thus excite or close the topological edge states. We further discussed the influence of plasma parameters on edge state characteristics, and the results showed that as the plasma density increased, the first photonic band gap (PBG) of the PPCs would be closed and then be reopened, resulting in band inversion and a change in the PBG properties of the PPCs. We can control the generation of edge states through plasma, and adjust the frequency and strength of the edge states. After the appearance of edge states, as the plasma density further increases, the first PBG of the PPCs will shift towards high frequencies and deepen. The frequency of edge states will shift towards higher frequencies, and their strength will also increase. We increased the first PBG depth of the PPCs by increasing the number of arrays, and found that when the number of the PPCs arrays increased, only the intensity of edge states would increase while the frequency remained unchanged. Therefore, flexible adjustment of edge states frequency and intensity can be achieved through the parameters of plasma density and array quantity. Our work demonstrates the properties of non-trivial edge states in plasma photonic crystals, which we believe can provide some guidance for applications based on edge states.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"53 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141650526","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}

{"title":"Investigating the occurrence and predictability of Pitch Angle Scattering events at ADITYA-Upgrade tokamak with the electron cyclotron emission radiometer","authors":"V. Siju, Santosh Pandya, S. K. Pathak, Ansh Patel, U. Nagora, Shishir Purohit, Samir K. Jha, Manoj Gupta, K. Tahiliani, Rohit Kumar Gupta, R. Tanna, Joydeep Ghosh","doi":"10.1088/2058-6272/ad62aa","DOIUrl":"https://doi.org/10.1088/2058-6272/ad62aa","url":null,"abstract":"\u0000 This paper describes the experimental analysis and preliminary investigation on the predictability of Pitch Angle Scattering (PAS) events through the Electron Cyclotron Emission (ECE) Radiometer signals at the ADITYA-Upgrade (ADITYA-U) tokamak. For low density discharges at ADITYA-U, a sudden abnormal rise is observed in the ECE signature while other plasma parameters are unchanged. Investigations are done to understand this abrupt rise that is expected to occur due to PAS. The rise time is as fast as 100 µs with a single step and/or multiple steps rise in ECE radiometer measurements. This event is known to limit the on-axis energy of runaway electrons. Being a repetitive event, the conditions of its repetitive occurrence can be investigated and thereby exploring the possibility of it being triggered and surveyed as an alternate runaway electron mitigation plan. Functional parameterization of such events with other discharge parameters is obtained and the possibility to trigger these events is discussed. PREDICT code is used to investigate the possible interpretations for the PAS occurrence through modeling and support the ECE observations. The trigger values so obtained experimentally are set as input criteria for PAS occurrence. Preliminary modeling investigations provide reliable consistency with the findings.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141654079","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}

{"title":"VUV imaging of type-Ⅰ ELM filamentary structures and their temporal characteristics on EAST","authors":"R. Deng, Tingfeng Ming, Bang Li, Q. Shi, S.W. Hou, Shuqi Yang, Xiaoju Liu, Shaocheng Liu, Guoqiang Li, Xiang Gao, Yasuhiro Suzuki, Yunfeng Liang","doi":"10.1088/2058-6272/ad621c","DOIUrl":"https://doi.org/10.1088/2058-6272/ad621c","url":null,"abstract":"\u0000 In the H-mode experiments conducted on the Experimental Advanced Superconducting Tokamak (EAST), fluctuations induced by the so-called edge localized modes (ELMs) are captured by a high-speed vacuum ultraviolet (VUV) imaging system. Clear field line-aligned filamentary structures are analyzed in this work. Ion transport induced by ELM filaments in the SOL under different discharge conditions is analyzed by comparing the VUV signals with the divertor probe signals. It is found that convective transport along open field lines towards the divertor target dominates the parallel ion particle transport mechanism during ELMs. The toroidal mode number of the filamentary structure derived from the VUV images increases with the electron density pedestal height. The analysis of the toroidal distribution characteristics during ELM bursts reveals toroidal asymmetry. The influence of resonance magnetic perturbation (RMP) on the ELM size is also analyzed using VUV imaging data. When the phase difference of the coil changes periodically, the widths of the filaments change as well. Additionally, the temporal evolution of the ELMs on the VUV signals provides rise time and decay time for each single ELM event, and the results indicate a negative correlation trend between these two times.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"89 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657645","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}

{"title":"Discharge and mass transfer characteristics of atmospheric pressure gas-solid two-phase gliding arc","authors":"Min Zhu, Yuchen Ping, Yinghao Zhang, Chaohai Zhang, Shuqun Wu","doi":"10.1088/2058-6272/ad61a2","DOIUrl":"https://doi.org/10.1088/2058-6272/ad61a2","url":null,"abstract":"\u0000 In this work, a gas-solid two-phase gliding arc discharge (GS-GAD) reactor was built. Gliding arc was formed in the gap between the blade electrodes, and solid powder was deposited on the sieve plate positioned beneath the blade electrodes. A range of experimental parameters, including the inter-electrode spacing, gas flow rate, applied voltage, and the type of the powder, were systematically varied to elucidate the influence of solid powder matter on the dynamics of gliding arc discharge (GAD). The discharge images were captured by ICCD and digital camera to investigate the mass transfer characteristics of GS-GAD, and the electrical parameters, such as the effective values of voltage, current, and discharge power were record to reveal the discharge characteristics of GS-GAD. The results demonstrate that powder undergoes spontaneous movement towards the upper region of the gliding arc due to the influence of electric field force. Increasing the discharge voltage, decreasing relative dielectric constant of the powder and reducing the electrode-to-sieve-plate distance all contribute to a greater involvement of powder in the GAD process, subsequently resulting in an enhanced powder concentration within the GAD region. Additionally, powder located beneath the gliding arc experiences downward resistance caused by the opposing gas flow and arc. Excessive gas flow rate notably hampers the powder concentration within the discharge region, and the velocity of powder motion in the upper part of the GAD region is reduced. Under the condition of electrode-to-sieve-plate distance of 30 mm, gas flow rate of 1.5 L/min, and peak-to-peak voltage of 31 kV, the best combination of arc gliding and powder spark discharge phenomena can be achieved with the addition of Al2O3 powder.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"86 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663004","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}

{"title":"Preliminary compact torus injection experiments on the Keda Torus eXperiment reversed field pinch","authors":"Tao Lan, Chen Chen, C. Xiao, Weixing Ding, Jie Wu, W. Mao, Sen Zhang, Defeng Kong, Shoubiao Zhang, Zhengwei Wu, Qi Dong, Yongkang Zhou, Hangqi Xu, Jiaren Wu, Zian Wei, X. Wen, Chu Zhou, Adi Liu, Hong Li, Jinlin Xie, Wandong Liu, Zhuang Ge","doi":"10.1088/2058-6272/ad60f4","DOIUrl":"https://doi.org/10.1088/2058-6272/ad60f4","url":null,"abstract":"\u0000 A new compact torus injector (KTX-CTI) has been built for injection experiments on the Keda Torus eXperiment (KTX) reversed field pinch (RFP). The aim is to study the fundamental physics governing the compact torus (CT) central fueling processes. In experiments conducted under the sole influence of a 0.1 T toroidal magnetic field, the injected CT successfully penetrated the entire toroidal magnetic field, reaching the inner wall of the KTX vacuum vessel. Upon reaching the inner wall, the CT diffused both radially outward and toroidally within the vessel at a discernible diffusion speed. Moreover, the inherent helicity within the CT induced a modest KTX plasma current of 200A, consistent with predictions based on helicity conservation. CT injection demonstrated the capability to initiate KTX discharges at low loop voltages, suggesting its potential as a pre-ionization and current startup technique. During RFP discharges featuring CT injection, the central plasma density was found to exceed the Greenwald density limit, with more peaked density profiles, indicating the predominant confinement of CT plasma within the core region of the KTX bulk plasma.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"68 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141664554","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}

{"title":"Interaction between the core and the edge for ion cyclotron resonance heating based on artificial absorption plasma model","authors":"Zhuoqi Liu, Jiahui Zhang, Kaibang Wu, Xinjun Zhang, Chengming Qin, Feng Wang, Zhengxiong Wang","doi":"10.1088/2058-6272/ad60f5","DOIUrl":"https://doi.org/10.1088/2058-6272/ad60f5","url":null,"abstract":"\u0000 In numerical simulations of the ion cyclotron range of frequencies (ICRF) wave heating scheme, core solvers usually focus on wave propagation and absorption mechanisms within the core plasma region. However, the realistic scrape-off layer (SOL) plasma is usually simplified, making it difficult to have deeper understanding of wave propagation and absorption within the SOL. In this work, we employ a cold plasma assumption and an artificial absorption mechanism based on the approach of reference (Zhang et al 2022 Nucl. Fusion 62 076032), to study wave propagation and absorption in the realistic SOL plasma of the EAST. During the exponential decay of the total coupled power with respect to the toroidal mode numbers, several fluctuations are observed in the case of low collisional frequencies. The fluctuations may be caused by the cavity modes associated with specific toroidal mode numbers. Due to the presence of cutoff densities, the edge power losses and the total coupled power exhibit different behaviors before and after the cut-off layer is “open”. Furthermore, the simulation results obtained from the kinetic model in reference (Zhang et al 2022 Nucl. Fusion 62 076032) is discussed. This suggests that both the core-edge combined model and the artificial mechanism are capable of simulating wave propagation and absorption.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"61 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663059","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}

{"title":"Effect of dielectric material on the uniformity of nanosecond pulsed dielectric barrier discharge","authors":"Wenhao Zhou, Dongxuan Zhang, Xiaohui Duan, Xi Zhu, Feng Liu, Z. Fang","doi":"10.1088/2058-6272/ad5fe6","DOIUrl":"https://doi.org/10.1088/2058-6272/ad5fe6","url":null,"abstract":"\u0000 Dielectric barrier discharge (DBD) is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure, and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge uniformity. In this work, the uniformity and discharge characteristics of the nanosecond (ns) pulsed DBD with dielectric barrier layers made of alumina, quartz glass, polycarbonate (PC), and polypropylene (PP) are investigated via discharge image observation, voltage-current waveform measurement and optical emission spectral diagnosis. Through analyzing discharge image by gray value standard deviation method, the discharge uniformity is quantitatively calculated. The effects of the space electric field intensity, the electron density (Ne), and the space reactive species on the uniformity are studied with quantifying the gap voltage Ug and the discharge current Ig, analyzing the recorded optical emission spectra, and simulating the temporal distribution of Ne with a one-dimensional fluid model. It is found that as the relative permittivity of the dielectric materials increases, the space electric field intensity is enhanced, which results in a higher Ne and electron temperature (Te). Therefore, an appropriate value of space electric field intensity can promote electron avalanches, resulting in uniform and stable plasma by the merging of electron avalanches. However, an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field, which reduce the discharge uniformity. The surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge uniformity. The results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity, and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pressure uniform, stable, and reactive plasma sources.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":" 32","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141672645","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}

{"title":"First results of turbulence investigation on Globus-M2 using radial correlation Doppler reflectometry","authors":"A. Ponomarenko, A. Yashin, V. Gusev, E. Kiselev, G. Kurskiev, V. Minaev, Y. Petrov, N. Sakharov, P. Shchegolev, E. Tkachenko, N. Zhiltsov","doi":"10.1088/2058-6272/ad5fe5","DOIUrl":"https://doi.org/10.1088/2058-6272/ad5fe5","url":null,"abstract":"\u0000 The first results of investigation of the turbulence structure using Doppler backscattering (DBS) on the Globus-M2 tokamak are presented. A one-channel DBS system with a variable probing frequency within the 18-26 GHz range was installed to investigate the edge plasma at normalized minor radii ρ = 0.9 – 1.1. Radial correlation Doppler reflectometry was used to study the changes in turbulence eddies after the LH transition. Correlation analysis was applied to the phase derivative of complex IQ signals of the DBS diagnostic as it contains information about the poloidal plasma rotation velocity. In L-mode the radial correlation length Lr is estimated to be 3 cm and after transition to H-mode reduces to approximately 2 cm. Gyrokinetic modelling in a linear local approximation using code GENE indicates that the instability with positive growth rates at the normalized minor radius ρ = 0.75 in L-mode and H-mode on Globus-M2 was the ion temperature gradient (ITG) mode.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":" 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141671747","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}

{"title":"Comparison of the effect of different external electrodes on discharge plasma-assisted diffusion flame stabilization","authors":"Siyin Zhou, Xiang Liu, Wansheng Nie, Shuhui Yuan","doi":"10.1088/2058-6272/ad5fe3","DOIUrl":"https://doi.org/10.1088/2058-6272/ad5fe3","url":null,"abstract":"\u0000 To optimize the design of plasma injectors, the influence of different external electrodes on plasma-assisted flame stabilization was assessed by using a nonequilibrium plasma injector flame control setup. The electrical characteristics of the injector, flame structure parameters, flame intensity, discharge power, and cost-to-effectiveness ratio under different external electrodes (four mesh electrodes and one copper foil electrode) were analyzed using electrical and optical methods. The results show that reducing the mesh size of the external electrode leads to a decrease in breakdown voltage. Compared with a ceramic dielectric barrier-based injector, an injector with a quartz dielectric barrier produces a higher breakdown voltage under the same conditions. For the same actuation voltage, the discharge current increases as the mesh size of the external electrode decreases, and combustion is enhanced by the discharge plasma; therefore, it is better to adopt a smaller mesh hole size to realize good flame stabilization under a lower actuation voltage. However, under the studied working conditions, reducing the mesh hole size of the external electrode increases the cost-to-effectiveness ratio of plasma injector-based flame stabilization. Thus, considering the cost-to-effectiveness ratio and the weight of the injector, an external electrode with a larger mesh hole size should be chosen, which contradicts the above rule.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":" 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141676956","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}

{"title":"Effect of rotating gliding discharges on the lean blow-off limit of biogas flames","authors":"Muhammad Saqib Akhtar, Mhedine Alicherif, Bing Wang, D. Lacoste","doi":"10.1088/2058-6272/ad5ec2","DOIUrl":"https://doi.org/10.1088/2058-6272/ad5ec2","url":null,"abstract":"\u0000 This study investigates the effect of a rotating gliding discharge on synthetic biogas combustion at atmospheric pressure. Synthetic biogas was produced by mixing methane and carbon dioxide. Three mixtures were considered: 100%-0%, 70%-30%, and 50%-50% of methane and carbon dioxide, respectively. The plasma effect was investigated in a low-swirl-number burner equipped with a high-voltage electrode to produce gliding discharges. The effect of plasma on the stability limits of the flame is reported for several electrical powers. During plasma-assisted combustion, the lean blow-off limits of biogas-air flames were significantly improved, which agrees with what can be found in the literature for other fuels. The electrical parameters of the discharge and the plasma emissions were measured using electric probes and emission spectroscopy, respectively. The mixture with the CO2 dilution was associated with a higher reduced electric field and higher ion production. A better understanding of the excited-species concentration evolution during plasma is necessary and will be investigated in future work.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"72 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141682369","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}