Nitrogen oxides (NOx) generated by discharge plasma with air have many application prospects in the fields of medicine, nitrogen fixation, energy and environmental protection. In this paper, high voltage AC power supply was used to excite cone-spiral electrodes to generate large area discharge, amount of gaseous NOx was generated, and then nitrogen dioxide (NO2) was converted to nitric oxide (NO) by a redox reactor molybdenum wire under high temperature conditions. The results show that the generations of NOx are affected by the applied discharge energies, frequencies and airflow states (1.31-2.62 m/s are the laminar flow, 2.62-5.24m/s are the transition state, 5.24- 6.55m /s are the turbulent flow). Moreover, the concentrations of NO, NO2 and NOx gradually increased, and the concentration ratios of NO/NO2 and NOx/NO2 decreased with increasing the discharge power from 104.2 J to 170.2 J. Meanwhile, the concentrations of NO, NO2 and NOx gradually decreased, and the concentration ratios of NO/NO2 and NOx/NO2 first decreased and then increased with increasing the applied frequency from 5.0 kHz to 9.0 kHz. Further, the concentrations of NO, NO2 and NOx gradually decreased, and the concentration ratios of NO/NO2 and NOx/NO2 first increased and then decreased with increasing the air flow speeds from 1.31 m/s to 6.55 m/s. Additionally, the concentrations of NO gradually increased while the concentration of NO2 gradually decreased and the concentration unchanged basically by adjusting the temperature of the high-temperature molybdenum converted reaction device from 25 ℃ to 350 ℃. This research can provide experimental support for the application of plasma in the fields of medicine, nitrogen fixation, energy and environmental protection.
{"title":"Synthesis of NO by rotating sliding arc discharge reactor with conical-spiral electrodes","authors":"Bingyan Chen, Qi Liu, Zhicheng Tang, Xu Li, Chunyang Zhang, Xiangbin Guo, Xiang He, Wei Su, Yongfeng Jiang","doi":"10.1088/2058-6272/ad6815","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6815","url":null,"abstract":"\u0000 Nitrogen oxides (NOx) generated by discharge plasma with air have many application prospects in the fields of medicine, nitrogen fixation, energy and environmental protection. In this paper, high voltage AC power supply was used to excite cone-spiral electrodes to generate large area discharge, amount of gaseous NOx was generated, and then nitrogen dioxide (NO2) was converted to nitric oxide (NO) by a redox reactor molybdenum wire under high temperature conditions. The results show that the generations of NOx are affected by the applied discharge energies, frequencies and airflow states (1.31-2.62 m/s are the laminar flow, 2.62-5.24m/s are the transition state, 5.24- 6.55m /s are the turbulent flow). Moreover, the concentrations of NO, NO2 and NOx gradually increased, and the concentration ratios of NO/NO2 and NOx/NO2 decreased with increasing the discharge power from 104.2 J to 170.2 J. Meanwhile, the concentrations of NO, NO2 and NOx gradually decreased, and the concentration ratios of NO/NO2 and NOx/NO2 first decreased and then increased with increasing the applied frequency from 5.0 kHz to 9.0 kHz. Further, the concentrations of NO, NO2 and NOx gradually decreased, and the concentration ratios of NO/NO2 and NOx/NO2 first increased and then decreased with increasing the air flow speeds from 1.31 m/s to 6.55 m/s. Additionally, the concentrations of NO gradually increased while the concentration of NO2 gradually decreased and the concentration unchanged basically by adjusting the temperature of the high-temperature molybdenum converted reaction device from 25 ℃ to 350 ℃. This research can provide experimental support for the application of plasma in the fields of medicine, nitrogen fixation, energy and environmental protection.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"8 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802129","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}
On J-TEXT, the temporal evolution of heat flux distribution on the high-field side (HFS) divertor plate has been measured by an infrared (IR) camera during the plasma operation with an island divertor configuration. In experiments, the island divertor configuration is an edge magnetic island chain structure surrounded by stochastic layers, which can be induced by resonant magnetic perturbations (RMPs). The experimental results show that the heat flux distribution on the HFS target plate depends significantly on the edge magnetic topology. Furthermore, the impact of Hydrogen fuelling by using supersonic molecular beam injection (SMBI) on the divertor heat flux distributions has also been studied on J-TEXT with an island divertor configuration. It has been observed that the power-detachment can be achieved when the radiation front approached the last closed flux surface (LCFS) after each SMBI pulse. This result may provide a method on access of divertor detachment on a fusion device with a three-dimensional (3D) boundary magnetic structure.
{"title":"Characteristics of divertor heat flux distribution with an island divertor configuration on the J-TEXT tokamak","authors":"Yutong Yang, Yunfeng Liang, Wei Yan, Shuangbao Shu, Jiankun Hua, Song Zhou, Qinghu Yang, Jinlong Guo, Ziyang Jin, Wei Xie","doi":"10.1088/2058-6272/ad6816","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6816","url":null,"abstract":"\u0000 On J-TEXT, the temporal evolution of heat flux distribution on the high-field side (HFS) divertor plate has been measured by an infrared (IR) camera during the plasma operation with an island divertor configuration. In experiments, the island divertor configuration is an edge magnetic island chain structure surrounded by stochastic layers, which can be induced by resonant magnetic perturbations (RMPs). The experimental results show that the heat flux distribution on the HFS target plate depends significantly on the edge magnetic topology. Furthermore, the impact of Hydrogen fuelling by using supersonic molecular beam injection (SMBI) on the divertor heat flux distributions has also been studied on J-TEXT with an island divertor configuration. It has been observed that the power-detachment can be achieved when the radiation front approached the last closed flux surface (LCFS) after each SMBI pulse. This result may provide a method on access of divertor detachment on a fusion device with a three-dimensional (3D) boundary magnetic structure.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"15 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141801994","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 dielectric barrier discharge (DBD) plasma actuator has been intensively investigated by researchers worldwide due to its simple structure, rapid response, and lack of mechanical moving parts. However, the limited discharge extension and uncontrollable induced jet direction restrict its engineering application. The tri-electrode sliding dielectric barrier discharge (TES-DBD) plasma actuator can overcome the above defects. However, the TES-DBD plasma actuator must be simultaneously driven by AC and DC power supplies, and the complex circuit connections and interactions between multiple power supplies increase energy consumption and system complexity. An integrated plasma supply suitable for the TES-DBD plasma actuators is designed to overcome the co-driven of multiple power supplies. The methodology encompasses designing the circuit topology for the TES-DBD power supply, followed by the simulation and validation of its operating principles utilizing Multisim software. The power supply's operational performance is assessed by comprehensively analyzing the electrical, thermal, and aerodynamic properties inherent to TES-DBD plasma actuation.
{"title":"Integrated design and performance optimization of three-electrode sliding discharge plasma power supply","authors":"Borui Zheng, Linwu Wang, Jianbo Zhang, Shaojie Qi, Yihong Chen, Haodong Liu, Dongliang Bian","doi":"10.1088/2058-6272/ad6814","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6814","url":null,"abstract":"\u0000 The dielectric barrier discharge (DBD) plasma actuator has been intensively investigated by researchers worldwide due to its simple structure, rapid response, and lack of mechanical moving parts. However, the limited discharge extension and uncontrollable induced jet direction restrict its engineering application. The tri-electrode sliding dielectric barrier discharge (TES-DBD) plasma actuator can overcome the above defects. However, the TES-DBD plasma actuator must be simultaneously driven by AC and DC power supplies, and the complex circuit connections and interactions between multiple power supplies increase energy consumption and system complexity. An integrated plasma supply suitable for the TES-DBD plasma actuators is designed to overcome the co-driven of multiple power supplies. The methodology encompasses designing the circuit topology for the TES-DBD power supply, followed by the simulation and validation of its operating principles utilizing Multisim software. The power supply's operational performance is assessed by comprehensively analyzing the electrical, thermal, and aerodynamic properties inherent to TES-DBD plasma actuation.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"60 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141799307","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 : 2024-07-26DOI: 10.1088/2058-6272/ad6817
Qing-Gang Zhou, Yanjie Zhang, C. Sang, Jiaxian Li, Guoyao Zheng, Yilin Wang, Yihan Wu, Dezhen Wang
Tungsten (W) accumulation in the core, depending on W generation and transport in the edge region, is a severe issue in fusion reactor. The divertor plasma parameters, such as heat flux to the target, can be effectively suppressed by changing the divertor magnetic configuration. Nevertheless, its impact on W core accumulation remains unclear. The HL-3 tokamak has advantage of operating with flexible divertor configurations, e.g. standard divertor (SD) and snowflake divertors (SFD). In this study, DIVIMP combined with SOLPS-ITER is applied to investigate the effects of divertor magnetic configurations (SD vs SFD) on W accumulation during neon injection in HL-3. It is found that W concentration in the core of SFD is significantly higher than that of SD with similar total W erosion flux. The reasons are: (1) W impurities in the core of SFD mainly originate from inner divertor, which has short leg, and the source is close to the divertor entrance and upstream separatrix. Furthermore, the SW0 is much stronger, especially near divertor entrance. (2) the region overlap of SW0 and F_(W,TOT) pointing to upstream promote W accumulation in the core. Moreover, influence of W source locations at inner target on W transport in the SFD is investigated. Tungsten impurity in the core is mainly contributed by target erosion at common flux region (CFR) away from strike point. This is attributed to that W source at this location enhances ionization source above the W ion stagnation point, which sequentially increases W penetration. Therefore, the suppression of far SOL inner target erosion can effectively prevent W impurities from accumulating in the core.
钨（W）在堆芯中的积累取决于 W 在边缘区域的生成和传输，这是聚变反应堆中的一个严重问题。通过改变岔流器的磁场配置，可以有效地抑制岔流器等离子体参数，如到达目标的热通量。尽管如此，它对 W 核积累的影响仍不明确。HL-3 托卡马克具有使用灵活的岔流器配置（如标准岔流器（SD）和雪花岔流器（SFD））的优势。在本研究中，DIVIMP 与 SOLPS-ITER 结合使用，研究了 HL-3 中子注入过程中分流器磁配置（SD 与 SFD）对 W 累积的影响。研究发现，在 W 总侵蚀通量相近的情况下，SFD 内核中的 W 浓度明显高于 SD 内核中的 W 浓度。原因如下(1) SFD 内核中的 W 杂质主要来源于内岔道，而内岔道支腿较短，且来源靠近岔道入口和上游分离矩阵。此外，SW0 的强度更大，尤其是在分流器入口附近。(2) SW0 和 F_(W,TOT)指向上游的重叠区域促进了 W 在堆芯中的积累。此外，还研究了内靶的 W 源位置对 W 在 SFD 中传输的影响。堆芯中的钨杂质主要是由远离打击点的共同通量区（CFR）的靶材侵蚀造成的。这是因为该位置的 W 源增强了 W 离子停滞点上方的电离源，从而增加了 W 的穿透力。因此，抑制远 SOL 内靶侵蚀可有效防止 W 杂质在堆芯中积累。
{"title":"Simulation of tungsten impurity transport by DIVIMP under different divertor magnetic configurations on HL-3","authors":"Qing-Gang Zhou, Yanjie Zhang, C. Sang, Jiaxian Li, Guoyao Zheng, Yilin Wang, Yihan Wu, Dezhen Wang","doi":"10.1088/2058-6272/ad6817","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6817","url":null,"abstract":"\u0000 Tungsten (W) accumulation in the core, depending on W generation and transport in the edge region, is a severe issue in fusion reactor. The divertor plasma parameters, such as heat flux to the target, can be effectively suppressed by changing the divertor magnetic configuration. Nevertheless, its impact on W core accumulation remains unclear. The HL-3 tokamak has advantage of operating with flexible divertor configurations, e.g. standard divertor (SD) and snowflake divertors (SFD). In this study, DIVIMP combined with SOLPS-ITER is applied to investigate the effects of divertor magnetic configurations (SD vs SFD) on W accumulation during neon injection in HL-3. It is found that W concentration in the core of SFD is significantly higher than that of SD with similar total W erosion flux. The reasons are: (1) W impurities in the core of SFD mainly originate from inner divertor, which has short leg, and the source is close to the divertor entrance and upstream separatrix. Furthermore, the SW0 is much stronger, especially near divertor entrance. (2) the region overlap of SW0 and F_(W,TOT) pointing to upstream promote W accumulation in the core. Moreover, influence of W source locations at inner target on W transport in the SFD is investigated. Tungsten impurity in the core is mainly contributed by target erosion at common flux region (CFR) away from strike point. This is attributed to that W source at this location enhances ionization source above the W ion stagnation point, which sequentially increases W penetration. Therefore, the suppression of far SOL inner target erosion can effectively prevent W impurities from accumulating in the core.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"46 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141800337","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 : 2024-07-24DOI: 10.1088/2058-6272/ad6704
Zuyu Zhang, T. Xu, Chijie Xiao, Xianli Huang, R. He, Ruixin Yuan, Xiaoyi Yang
The poloidal magnetic field (B_p) plays a critical role in plasma equilibrium, confinement and transport of magnetic confinement devices. Multiple diagnostic methods are needed to complement each other to obtain a more accurate B_p profile. Recently, the laser-driven ion-beam trace probe (LITP) has been proposed as a promising tool for diagnosing B_p and radial electric field (E_r) profiles in tokamaks [Yang X Y et al 2014 Rev. Sci. Instrum. 85 11E429]. The spherical tokamak (ST) is a promising compact device with high plasma beta and naturally large elongation. However, when applying LITP to diagnosing B_p in STs, the larger B_p invalidates the linear reconstruction relationship for conventional tokamaks, necessitating the development of a nonlinear reconstruction principle tailored to STs. This novel approach employs an iterative reconstruction method based on Newton’s method to solve the nonlinear equation. Subsequently, a simulation model to reconstruct the B_p profile of STs is developed and the experimental setup of LITP is designed for EXL-50, a middle-sized ST. Simulation results of the reconstruction show that the relative errors of B_p reconstruction are mostly below 5%. Moreover, even with 5 mm measurement error on beam traces or 1 cm flux surface shape error, the average relative error of reconstruction remains below 15%, initially demonstrating the robustness of LITP in diagnosing B_p profiles in STs.
极性磁场（B_p）在磁约束装置的等离子体平衡、约束和传输中起着至关重要的作用。要获得更精确的 B_p 曲线，需要多种诊断方法相互补充。最近，有人提出激光驱动离子束痕量探测器（LITP）是诊断托卡马克中 B_p 和径向电场（E_r）剖面的一种很有前途的工具[Yang X Y et al 2014 Rev. Sci. Instrum.］球形托卡马克（ST）是一种很有前途的紧凑型装置，具有高等离子体贝塔和天然的大伸长率。然而，当应用 LITP 诊断 ST 中的 B_p 时，较大的 B_p 使传统托卡马克的线性重构关系失效，因此有必要开发一种适合 ST 的非线性重构原理。这种新方法采用基于牛顿法的迭代重建方法来求解非线性方程。随后，建立了重建 ST 的 B_p 剖面的模拟模型，并为中型 ST EXL-50 设计了 LITP 实验装置。重建的模拟结果表明，B_p 重建的相对误差大多低于 5%。此外，即使存在 5 毫米的光束轨迹测量误差或 1 厘米的通量表面形状误差，重建的平均相对误差仍低于 15%，初步证明了 LITP 在诊断 ST 的 B_p 轮廓方面的鲁棒性。
{"title":"Poloidal magnetic field reconstruction by laser-driven ion-beam trace probe in spherical tokamak","authors":"Zuyu Zhang, T. Xu, Chijie Xiao, Xianli Huang, R. He, Ruixin Yuan, Xiaoyi Yang","doi":"10.1088/2058-6272/ad6704","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6704","url":null,"abstract":"\u0000 The poloidal magnetic field (B_p) plays a critical role in plasma equilibrium, confinement and transport of magnetic confinement devices. Multiple diagnostic methods are needed to complement each other to obtain a more accurate B_p profile. Recently, the laser-driven ion-beam trace probe (LITP) has been proposed as a promising tool for diagnosing B_p and radial electric field (E_r) profiles in tokamaks [Yang X Y et al 2014 Rev. Sci. Instrum. 85 11E429]. The spherical tokamak (ST) is a promising compact device with high plasma beta and naturally large elongation. However, when applying LITP to diagnosing B_p in STs, the larger B_p invalidates the linear reconstruction relationship for conventional tokamaks, necessitating the development of a nonlinear reconstruction principle tailored to STs. This novel approach employs an iterative reconstruction method based on Newton’s method to solve the nonlinear equation. Subsequently, a simulation model to reconstruct the B_p profile of STs is developed and the experimental setup of LITP is designed for EXL-50, a middle-sized ST. Simulation results of the reconstruction show that the relative errors of B_p reconstruction are mostly below 5%. Moreover, even with 5 mm measurement error on beam traces or 1 cm flux surface shape error, the average relative error of reconstruction remains below 15%, initially demonstrating the robustness of LITP in diagnosing B_p profiles in STs.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809983","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 : 2024-07-24DOI: 10.1088/2058-6272/ad6705
Ziming Zhang, Chuan Fang, Yaoting Wang, Lanyue Luo, Heping Li
The key plasma parameters under different discharge modes, e.g., the heavy-particle and electron temperatures, the electron number density, the non-equilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this paper, a self-consistent two-dimensional non-equilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes including the normal glow, abnormal glow, arc, and the glow-to-arc transition mode with the atmospheric-pressure direct-current (DC) argon discharge as a model plasma system. The modeling results show that under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On the one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, while the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux towards the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and the plasma column under the arc mode with the increase of the discharge current. Consequently, the power density in the cathode sheath (Pc ) is used as a key parameter for judging different discharge modes. And the range of (0.28 ~ 1.2)×1012 W·m-3 is determined as a critical window of Pc corresponding to the glow-to-arc mode transition for the atmospheric-pressure DC argon discharges, which is also verified well by comparing with the experimental results in this study and the data in the previous literatures.
不同放电模式下的关键等离子体参数，如重粒子和电子温度、电子数密度、等离子体的非平衡体积等，在气体放电等离子体的各种应用中发挥着重要作用。本文以大气压直流氩气放电为模型等离子体系统，建立了自洽的二维非平衡流体模型和外电路模型，揭示了正常辉光、异常辉光、电弧和辉光到电弧过渡模式等放电模式的相关机理。建模结果表明，在不同的放电模式下，前四种放电模式的最大区别在于阴极侧的电流和能量传递过程。一方面，在辉光放电模式下，由于固体阴极温度较低，流向阴极表面的电流主要由来自等离子体柱的离子提供；而在电弧模式下，阴极表面温度较高，流向阴极的离子通量较大，热阴极表面发射的热电子和二次电子发挥了非常重要的作用。另一方面，随着放电电流的增加，阴极侧的能量传递通道也发生了变化，从辉光模式下主要加热固体阴极，变为电弧模式下同时加热固体阴极和等离子体柱。因此，阴极鞘内的功率密度（Pc ）被用作判断不同放电模式的关键参数。并确定了大气压直流氩气放电从辉光模式到电弧模式转变所对应的 Pc 临界窗口范围为 (0.28 ~ 1.2)×1012 W-m-3，通过与本研究的实验结果和之前文献中的数据进行比较，也得到了很好的验证。
{"title":"Analyses of non-equilibrium transports in atmospheric-pressure direct-current argon discharges under different modes","authors":"Ziming Zhang, Chuan Fang, Yaoting Wang, Lanyue Luo, Heping Li","doi":"10.1088/2058-6272/ad6705","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6705","url":null,"abstract":"\u0000 The key plasma parameters under different discharge modes, e.g., the heavy-particle and electron temperatures, the electron number density, the non-equilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this paper, a self-consistent two-dimensional non-equilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes including the normal glow, abnormal glow, arc, and the glow-to-arc transition mode with the atmospheric-pressure direct-current (DC) argon discharge as a model plasma system. The modeling results show that under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On the one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, while the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux towards the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and the plasma column under the arc mode with the increase of the discharge current. Consequently, the power density in the cathode sheath (Pc\u0000 ) is used as a key parameter for judging different discharge modes. And the range of (0.28 ~ 1.2)×1012 W·m-3 is determined as a critical window of Pc\u0000 corresponding to the glow-to-arc mode transition for the atmospheric-pressure DC argon discharges, which is also verified well by comparing with the experimental results in this study and the data in the previous literatures.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"78 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141807971","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 : 2024-07-24DOI: 10.1088/2058-6272/ad6706
Meng yu Wang, Jianping Liang, Ke Lu, Zikai Zhou, Qing hua Liu, Hao Yuan, Wenchun Wang, Dezheng Yang
In recent years, antibiotic pollution has become a serious threat to human health. In this paper, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containing inorganic and organic impurities. The discharge characteristics are analyzed by diagnosing the applied voltage and discharge current waveforms, as well as the optical emission spectra. The work investigates how degradation efficiency is affected by applied voltage, gas flow rate, treatment time, initial concentration as well as the addition of γ-Al2O3 pellets and peanut straw. After 70 min, the degradation efficiency of ciprofloxacin hydrochloride in the multiphase mixed system reached 99.6%. Its removal efficiency increases as the initial concentration decreases and the applied voltage increases. Besides, there is still a good degradation efficiency of ciprofloxacin hydrochloride with the addition of peanut straw. The degradation mechanism of ciprofloxacin hydrochloride is investigated through the analysis of degraded intermediates and reactive species.
{"title":"Degradation of ciprofloxacin hydrochloride in a multiphase mixed system by subaquatic gas-liquid discharge plasma","authors":"Meng yu Wang, Jianping Liang, Ke Lu, Zikai Zhou, Qing hua Liu, Hao Yuan, Wenchun Wang, Dezheng Yang","doi":"10.1088/2058-6272/ad6706","DOIUrl":"https://doi.org/10.1088/2058-6272/ad6706","url":null,"abstract":"\u0000 In recent years, antibiotic pollution has become a serious threat to human health. In this paper, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containing inorganic and organic impurities. The discharge characteristics are analyzed by diagnosing the applied voltage and discharge current waveforms, as well as the optical emission spectra. The work investigates how degradation efficiency is affected by applied voltage, gas flow rate, treatment time, initial concentration as well as the addition of γ-Al2O3 pellets and peanut straw. After 70 min, the degradation efficiency of ciprofloxacin hydrochloride in the multiphase mixed system reached 99.6%. Its removal efficiency increases as the initial concentration decreases and the applied voltage increases. Besides, there is still a good degradation efficiency of ciprofloxacin hydrochloride with the addition of peanut straw. The degradation mechanism of ciprofloxacin hydrochloride is investigated through the analysis of degraded intermediates and reactive species.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"34 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809986","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, the effects of the frequency, pressure, gas composition, and secondary-electron emission coefficient on the discharge mode in capacitively coupled Ar/O2 plasmas were carefully studied through simulations. Three discharge modes α, γ, and drift-ambipolar (DA) were considered in this study. The α mode involves electron power absorption resulting from interactions between free electrons and the expanded plasma sheath; the γ mode is dominated by secondary-electron heating; and the DA mode is electron power absorption mainly produced by the drift electric field in the plasma region and the ambipolar electric field at the edge of the sheath. The results show that a mode transition from the γ-DA hybrid mode dominated by the γ mode to the DA-α hybrid mode dominated by the DA mode is induced by increasing the frequency from 100 kHz to 40 MHz. Furthermore, the electron temperature decreases with increasing frequency, while the plasma density first decreases and then increases. It was found that the electronegativity increases slightly with increasing pressure in the low-frequency region, and it increases notably with increasing pressure in the high-frequency region. It was also observed that the frequency corresponding to the mode transition from γ to DA decreased when the secondary-electron emission coefficient was decreased. Finally, it was found that increasing the oxygen content weakens the γ mode and enhances the DA mode. More importantly, the density of oxygen atoms and ozone will increase greatly with increasing oxygen content, which is of great significance for industrial applications.
本研究通过模拟仔细研究了频率、压力、气体成分和二次电子发射系数对电容耦合氩/氧等离子体放电模式的影响。本研究考虑了三种放电模式α、γ和漂移双极（DA）。α 模式涉及自由电子与膨胀等离子体鞘相互作用产生的电子功率吸收；γ 模式主要由二次电子加热产生；而 DA 模式则主要由等离子体区域的漂移电场和鞘边缘的伏极电场产生的电子功率吸收。结果表明，当频率从 100 kHz 提高到 40 MHz 时，γ 模主导的 γ-DA 混合模会转变为 DA 模主导的 DA-α 混合模。此外，电子温度随频率升高而降低，等离子体密度则先降低后升高。研究发现，在低频区，电负性随着压力的增加而略有增加，而在高频区，电负性则随着压力的增加而显著增加。还观察到，当二次电子发射系数降低时，从 γ 到 DA 的模式转换所对应的频率也会降低。最后，研究发现，增加氧含量会减弱 γ 模式，增强 DA 模式。更重要的是，氧原子和臭氧的密度会随着氧含量的增加而大大增加，这对工业应用具有重要意义。
{"title":"Simulation of mode transitions in capacitively coupled Ar/O2 plasmas","authors":"Xiangmei Liu, Shuren Zhang, Shuxia Zhao, Hong-Yi Li, Xiaohui Ren","doi":"10.1088/2058-6272/ad668d","DOIUrl":"https://doi.org/10.1088/2058-6272/ad668d","url":null,"abstract":"\u0000 In this work, the effects of the frequency, pressure, gas composition, and secondary-electron emission coefficient on the discharge mode in capacitively coupled Ar/O2 plasmas were carefully studied through simulations. Three discharge modes α, γ, and drift-ambipolar (DA) were considered in this study. The α mode involves electron power absorption resulting from interactions between free electrons and the expanded plasma sheath; the γ mode is dominated by secondary-electron heating; and the DA mode is electron power absorption mainly produced by the drift electric field in the plasma region and the ambipolar electric field at the edge of the sheath. The results show that a mode transition from the γ-DA hybrid mode dominated by the γ mode to the DA-α hybrid mode dominated by the DA mode is induced by increasing the frequency from 100 kHz to 40 MHz. Furthermore, the electron temperature decreases with increasing frequency, while the plasma density first decreases and then increases. It was found that the electronegativity increases slightly with increasing pressure in the low-frequency region, and it increases notably with increasing pressure in the high-frequency region. It was also observed that the frequency corresponding to the mode transition from γ to DA decreased when the secondary-electron emission coefficient was decreased. Finally, it was found that increasing the oxygen content weakens the γ mode and enhances the DA mode. More importantly, the density of oxygen atoms and ozone will increase greatly with increasing oxygen content, which is of great significance for industrial applications.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"17 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141813798","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 : 2024-07-22DOI: 10.1088/2058-6272/ad663b
Zhipeng Chen, Zhangsheng Huang, Min Jiang, T. Long, Lu Wang, Weixin Guo, Zhoujun Yang, Hai Liu, Tao Lan, Kaijun Zhao, Yuhong Xu, R. Ke, Youwen Sun, Hanhui Li, Wen He, Zhuang Ge, Yuejiang Shi, Wulyu Zhong, Yonghua Ding, Yunfeng Liang, Wenjing Tian, Xin Xu, Guodong Zhang, Malik Sadam Hussain, Patrick Diamond
Following the reconstruction of the TEXT tokamak in China at Huazhong University of Science and Technology, renamed as J-TEXT, a plethora of experimental and theoretical investigations have been conducted to elucidate the intricacies of turbulent transport within the tokamak configuration. These endeavors encompass not only the J-TEXT device's experimental advancements but also delve into critical issues pertinent to the optimization of future fusion devices and reactors. The researches include the topics about the suppression of turbulence, flow drive and damping, density limit, nonlocal transport, intrinsic toroidal flow, turbulence and flow with magnetic island, turbulent transport in stochastic layer, turbulence and zonal flow with energetic particles or helium ash. Several important achievements have been got in the last few years, which will be further elaborated upon in this comprehensive review.
在中国华中科技大学重建 TEXT 托卡马克（更名为 J-TEXT）之后，进行了大量的实验和理论研究，以阐明托卡马克构型内湍流输运的复杂性。这些工作不仅包括 J-TEXT 设备的实验进展，还深入研究了与未来聚变设备和反应堆优化相关的关键问题。研究内容包括湍流抑制、流动驱动和阻尼、密度极限、非局部传输、本征环形流、磁岛湍流和流动、随机层中的湍流传输、高能粒子或氦灰湍流和带状流。过去几年中取得了一些重要成果，本综合综述将对这些成果作进一步阐述。
{"title":"J-TEXT achievements in turbulence and transport in support of future device/reactor","authors":"Zhipeng Chen, Zhangsheng Huang, Min Jiang, T. Long, Lu Wang, Weixin Guo, Zhoujun Yang, Hai Liu, Tao Lan, Kaijun Zhao, Yuhong Xu, R. Ke, Youwen Sun, Hanhui Li, Wen He, Zhuang Ge, Yuejiang Shi, Wulyu Zhong, Yonghua Ding, Yunfeng Liang, Wenjing Tian, Xin Xu, Guodong Zhang, Malik Sadam Hussain, Patrick Diamond","doi":"10.1088/2058-6272/ad663b","DOIUrl":"https://doi.org/10.1088/2058-6272/ad663b","url":null,"abstract":"\u0000 Following the reconstruction of the TEXT tokamak in China at Huazhong University of Science and Technology, renamed as J-TEXT, a plethora of experimental and theoretical investigations have been conducted to elucidate the intricacies of turbulent transport within the tokamak configuration. These endeavors encompass not only the J-TEXT device's experimental advancements but also delve into critical issues pertinent to the optimization of future fusion devices and reactors. The researches include the topics about the suppression of turbulence, flow drive and damping, density limit, nonlocal transport, intrinsic toroidal flow, turbulence and flow with magnetic island, turbulent transport in stochastic layer, turbulence and zonal flow with energetic particles or helium ash. Several important achievements have been got in the last few years, which will be further elaborated upon in this comprehensive review.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141815820","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 : 2024-07-19DOI: 10.1088/2058-6272/ad659f
Peng Deng, W. Mao, Zhipeng Chen, Yinan Zhou, Peng Shi, Zhoujun Yang, Liutian Gao, Tao Lan, Jinlin Xie, Hong Li, Zian Wei, Adi Liu, Chu Zhou, Weixing Ding, Wandong Liu, Zhuang Ge
Density limit has long been a widely studied issue influencing the operating range of tokamaks. The rapid growth of the m/n = 2/1 (where m and n are poloidal and toroidal mode numbers, respectively) tearing mode is generally regarded as a primary precursor to the density limit disruption. In this experiment, the coupling of the m/n=1/1 mode and the m/n = 2/1 mode in high density plasma was observed. During a sawtooth cycle, the frequencies of the two modes gradually converge until they become equal. After that, toroidal coupling occurs between the 1/1 and 2/1 modes, resulting in a mutually fixed phase relationship. With the occurrence of toroidal coupling, the 2/1 mode will be stabilized. Prior to the disruption, the cessation of the 1/1 and 2/1 mode coupling, along with the rapid growth in the amplitude of the 2/1 mode, can be observed. Additionally, under the same parameters, comparing discharges with or without the 1/1 mode, it is found that the presence of the 1/1 mode leads to higher plasma density and temperature parameters.
{"title":"The impact of toroidal mode coupling on high-density discharges in J-TEXT","authors":"Peng Deng, W. Mao, Zhipeng Chen, Yinan Zhou, Peng Shi, Zhoujun Yang, Liutian Gao, Tao Lan, Jinlin Xie, Hong Li, Zian Wei, Adi Liu, Chu Zhou, Weixing Ding, Wandong Liu, Zhuang Ge","doi":"10.1088/2058-6272/ad659f","DOIUrl":"https://doi.org/10.1088/2058-6272/ad659f","url":null,"abstract":"\u0000 Density limit has long been a widely studied issue influencing the operating range of tokamaks. The rapid growth of the m/n = 2/1 (where m and n are poloidal and toroidal mode numbers, respectively) tearing mode is generally regarded as a primary precursor to the density limit disruption. In this experiment, the coupling of the m/n=1/1 mode and the m/n = 2/1 mode in high density plasma was observed. During a sawtooth cycle, the frequencies of the two modes gradually converge until they become equal. After that, toroidal coupling occurs between the 1/1 and 2/1 modes, resulting in a mutually fixed phase relationship. With the occurrence of toroidal coupling, the 2/1 mode will be stabilized. Prior to the disruption, the cessation of the 1/1 and 2/1 mode coupling, along with the rapid growth in the amplitude of the 2/1 mode, can be observed. Additionally, under the same parameters, comparing discharges with or without the 1/1 mode, it is found that the presence of the 1/1 mode leads to higher plasma density and temperature parameters.","PeriodicalId":506986,"journal":{"name":"Plasma Science and Technology","volume":"107 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821759","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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