Pub Date : 2024-05-16DOI: 10.1088/1361-6595/ad4c94
Vladislav Kotov, C. Kiefer, Ante Hecimovic
The CO2→CO+½O2 conversion experiment [F~A~D’Isa et al. 2020 Plasma Sources Sci. Technol. 29 105009] has been compared with thermo-chemical calculations. The experiment is a 2.45 GHz plasma torch with straight channel in the effluent. The 1.5D model of the CO2/CO/O2/O/C mixture without turbulent transport has been applied with plasma acting only as prescribed heat source. The parameter range covered is specific energy input (SEI) 0.3-5 eV/molecule at pressure p=0.9 bar, and SEI=0.6-2 eV/molecule at p=0.5, 0.2 bar. The calculated conversion χ is always close to experimental values. At the same time, the calculated temperatures T deviate significantly from the experiment, especially for p=0.2 bar. The calculated T were also found to be sensitive with respect to the uncertain model parameters, but χ is not sensitive. According to the model the net conversion is driven mainly by the radial diffusion of CO and O from the hot core toward the wall and steep radial temperature gradients. The main factor which reduces the energy efficiency is re-oxidation of CO at the edge of the hot plasma region and downstream. The net conversion in the model is driven to large extent by the radial diffusion of CO and O from the hot core toward the wall and steep radial temperature gradients. The main factor which reduces the energy efficiency is re-oxidation of CO at the edge of the hot plasma region and downstream. The 1.5D approximation applied has the principle limitation that the impact of the realistic bulk flow field on the chemical process could not be studied. Hence the results must be considered as preliminary and have to be confirmed with a more elaborate and accurate model of the vortex stabilized flows inside the reactor.
CO2→CO+½O2 转换实验 [F~A~D'Isa 等人，2020 等离子体源科学与技术，29 105009] 与热化学计算进行了比较。该实验采用 2.45 GHz 等离子体炬，流出物为直通道。CO2/CO/O2/O/C 混合物的 1.5D 模型没有湍流传输，等离子体仅作为规定热源。参数范围为：压力 p=0.9 巴时，比能量输入（SEI）为 0.3-5 eV/分子；压力 p=0.5 和 0.2 巴时，比能量输入（SEI）为 0.6-2 eV/分子。计算出的转化率 χ 始终接近实验值。同时，计算得到的温度 T 与实验值偏差很大，尤其是在 p=0.2 巴时。计算得出的 T 对不确定的模型参数也很敏感，但 χ 并不敏感。根据模型，净转换主要是由 CO 和 O 从热核向壁的径向扩散以及陡峭的径向温度梯度驱动的。降低能量效率的主要因素是热等离子体区域边缘和下游 CO 的再氧化。模型中的净转换在很大程度上是由 CO 和 O 从热核向壁面的径向扩散以及陡峭的径向温度梯度驱动的。降低能量效率的主要因素是 CO 在热等离子体区域边缘和下游的再氧化。所采用的 1.5D 近似方法有一个原则性的限制，即无法研究现实的大体流场对化学过程的影响。因此，必须将这些结果视为初步结果，并通过对反应器内的涡流稳定流建立更复杂、更精确的模型来加以证实。
{"title":"Validation of the thermo-chemical approach to modelling of the CO2 conversion in sub-atmospheric pressure microwave gas discharges","authors":"Vladislav Kotov, C. Kiefer, Ante Hecimovic","doi":"10.1088/1361-6595/ad4c94","DOIUrl":"https://doi.org/10.1088/1361-6595/ad4c94","url":null,"abstract":"\u0000 The CO2→CO+½O2 conversion experiment [F~A~D’Isa et al. 2020 Plasma Sources Sci. Technol.\u0000 29 105009] has been compared with thermo-chemical calculations. The experiment is a 2.45 GHz plasma torch with straight channel in the effluent. The 1.5D model of the CO2/CO/O2/O/C mixture without turbulent transport has been applied with plasma acting only as prescribed heat source. The parameter range covered is specific energy input (SEI) 0.3-5 eV/molecule at pressure p=0.9 bar, and SEI=0.6-2 eV/molecule at p=0.5, 0.2 bar. The calculated conversion χ is always close to experimental values. At the same time, the calculated temperatures T deviate significantly from the experiment, especially for p=0.2 bar. The calculated T were also found to be sensitive with respect to the uncertain model parameters, but χ is not sensitive. According to the model the net conversion is driven mainly by the radial diffusion of CO and O from the hot core toward the wall and steep radial temperature gradients. The main factor which reduces the energy efficiency is re-oxidation of CO at the edge of the hot plasma region and downstream. The net conversion in the model is driven to large extent by the radial diffusion of CO and O from the hot core toward the wall and steep radial temperature gradients. The main factor which reduces the energy efficiency is re-oxidation of CO at the edge of the hot plasma region and downstream. The 1.5D approximation applied has the principle limitation that the impact of the realistic bulk flow field on the chemical process could not be studied. Hence the results must be considered as preliminary and have to be confirmed with a more elaborate and accurate model of the vortex stabilized flows inside the reactor.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"32 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140968636","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 : 2024-05-13DOI: 10.1088/1361-6595/ad4ac3
Zening Du, Zhiwen Wu, Jin Li, Wei Sun, Pengkun Li, Yuntao Guo
Ionic liquid electrospray thruster (ILET) has the advantages of high specific impulse, precise thrust control, and low structural mass, which make it ideal for small satellites. The charged particles of ILET’s plume may lead to device charging or even damage, restricting its engineering applications. Thus, this paper examines the self-neutralization effectiveness of the ILET's plume under various emission conditions using particle-in-cell simulations. In order to accurately evaluate the self-neutralization effectiveness of the ILET’s plume, the median potential is explained in this paper and its reasonableness as the evaluation criterion for self-neutralization of the plume is verified. The working envelope for achieving self-neutralization of the ILET’s plume is determined by simulating the bipolar plume under various emission conditions. The results indicate that when the highest and lowest potentials are the same, the mean electric field strength between two points in space with a better degree of neutrality is 200% higher compared to points with a lesser degree of neutrality. The study determines the working envelope to realize self-neutralization of the ILET’s plume with an effectiveness of 70%. When the emission voltage of the anode thruster is fixed, the range of the cathode thruster’s voltage ranges from 108.36 V to 228.74 V. The asymmetry between the anode and cathode emissions of the ILET prototype significantly influences the operational range of the cathode thruster. Greater asymmetry leads to a narrower operating range for the ILET to achieve self-neutralization of the plume. This study serves as a guide for the ILET to achieve self-neutralization of the plume.
离子液体电喷推进器（ILET）具有比冲大、推力控制精确、结构质量小等优点，是小型卫星的理想推进器。离子液体电喷推进器羽流中的带电粒子可能导致设备带电甚至损坏，限制了其工程应用。因此，本文利用粒子入胞模拟法研究了 ILET 烟羽在各种发射条件下的自中和效果。为了准确评估 ILET 烟羽的自中性化效果，本文解释了中值电位，并验证了其作为烟羽自中性化评估标准的合理性。通过模拟不同排放条件下的双极烟羽，确定了实现 ILET 烟羽自中性化的工作包络线。结果表明，当最高电位和最低电位相同时，空间中性程度较高的两点之间的平均电场强度比中性程度较低的两点之间的平均电场强度高 200%。研究确定了实现 ILET 烟羽自中性化的工作包络线，其有效性为 70%。当阳极推进器的发射电压固定时，阴极推进器的电压范围在 108.36 V 至 228.74 V 之间。不对称程度越大，ILET 实现羽流自中和的工作范围就越窄。这项研究为 ILET 实现羽流自中和提供了指导。
{"title":"Study on the plume self-neutralization of ionic liquid electrospray thruster based on median potential","authors":"Zening Du, Zhiwen Wu, Jin Li, Wei Sun, Pengkun Li, Yuntao Guo","doi":"10.1088/1361-6595/ad4ac3","DOIUrl":"https://doi.org/10.1088/1361-6595/ad4ac3","url":null,"abstract":"\u0000 Ionic liquid electrospray thruster (ILET) has the advantages of high specific impulse, precise thrust control, and low structural mass, which make it ideal for small satellites. The charged particles of ILET’s plume may lead to device charging or even damage, restricting its engineering applications. Thus, this paper examines the self-neutralization effectiveness of the ILET's plume under various emission conditions using particle-in-cell simulations. In order to accurately evaluate the self-neutralization effectiveness of the ILET’s plume, the median potential is explained in this paper and its reasonableness as the evaluation criterion for self-neutralization of the plume is verified. The working envelope for achieving self-neutralization of the ILET’s plume is determined by simulating the bipolar plume under various emission conditions. The results indicate that when the highest and lowest potentials are the same, the mean electric field strength between two points in space with a better degree of neutrality is 200% higher compared to points with a lesser degree of neutrality. The study determines the working envelope to realize self-neutralization of the ILET’s plume with an effectiveness of 70%. When the emission voltage of the anode thruster is fixed, the range of the cathode thruster’s voltage ranges from 108.36 V to 228.74 V. The asymmetry between the anode and cathode emissions of the ILET prototype significantly influences the operational range of the cathode thruster. Greater asymmetry leads to a narrower operating range for the ILET to achieve self-neutralization of the plume. This study serves as a guide for the ILET to achieve self-neutralization of the plume.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"66 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140983405","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 : 2024-05-08DOI: 10.1088/1361-6595/ad48b5
K. Polášková, Petr Drexler, Miloš Klíma, Jan Macháč, D. Nečas, M. Svanda, Lenka Zajíčková
The cold atmospheric plasma jets change their character when interacting with the different surfaces. Since such interaction is the primary area of plasma jet applications, it is essential to monitor the process. The non-linearity of the RF plasma slit jet (PSJ) was analyzed using the VI probes and a novel method, the non- intrusive antenna measurements. Regardless of the experimental setup and gas mixture (Ar, Ar/O2 , Ar/N2), the PSJ frequency spectrum consisted of the following main features: dominant fundamental frequency peak, relatively strong odd harmonics, and significantly weaker even harmonics. The lowest degree of non-linearity was recorded for the Ar PSJ ignited against a grounded target. Admixing a molecular gas increased the discharge non-linearity as observed by even harmonics intensities. It was attributed to the enhancement of secondary electron emission from the dielectric surfaces. In addition to the non-linearity analysis, the antenna spectra were for the first time used to determine the semi-quantative values of the PSJ-radiated electric field. The electric fields decreased by a factor of 2 after the admixing of nitrogen and oxygen molecular gases. Out of the studied targets, the highest electric fields were observed when plasma impinged on the grounded targets, followed by the floating target (2x lower) and the PSJ ignited in the open space configuration (4x lower than in the grounded target configuration).
{"title":"Electric field and higher harmonics of RF plasma slit jet measured by antennas and VI probes","authors":"K. Polášková, Petr Drexler, Miloš Klíma, Jan Macháč, D. Nečas, M. Svanda, Lenka Zajíčková","doi":"10.1088/1361-6595/ad48b5","DOIUrl":"https://doi.org/10.1088/1361-6595/ad48b5","url":null,"abstract":"\u0000 The cold atmospheric plasma jets change their character when interacting with the different surfaces. Since such interaction is the primary area of plasma jet applications, it is essential to monitor the process. The non-linearity of the RF plasma slit jet (PSJ) was analyzed using the VI probes and a novel method, the non- intrusive antenna measurements. Regardless of the experimental setup and gas mixture (Ar, Ar/O2 , Ar/N2), the PSJ frequency spectrum consisted of the following main features: dominant fundamental frequency peak, relatively strong odd harmonics, and significantly weaker even harmonics. The lowest degree of non-linearity was recorded for the Ar PSJ ignited against a grounded target. Admixing a molecular gas increased the discharge non-linearity as observed by even harmonics intensities. It was attributed to the enhancement of secondary electron emission from the dielectric surfaces. In addition to the non-linearity analysis, the antenna spectra were for the first time used to determine the semi-quantative values of the PSJ-radiated electric field. The electric fields decreased by a factor of 2 after the admixing of nitrogen and oxygen molecular gases. Out of the studied targets, the highest electric fields were observed when plasma impinged on the grounded targets, followed by the floating target (2x lower) and the PSJ ignited in the open space configuration (4x lower than in the grounded target configuration).","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":" 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140999692","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 : 2024-05-03DOI: 10.1088/1361-6595/ad473f
Simon Böddeker, Sven Gröger, N. Bibinov, P. Awakowicz
A gliding arc plasmatron (GAP) is a promising warm plasma source for the use in gas conversion applications but lacks an understanding of the plasma dynamics. In this paper, the gliding arc plasma conditions of a GAP operated with nitrogen flow (10 slm) are characterized using optical emission spectroscopy (OES) and numerical simulation. A simultaneously two-wavelength OES method and Abel inversion of the measured images with a spatial resolution of 19.6 μm are applied. The collisional radiative model used in this study includes Coulomb collisions of electrons. An iterative method of plasma parameter determination is applied. The determined values of the electric field up to 49 Td and electron density up to 2.5∙10^15 cm-3 fit well to the plasma parameters received with different diagnostics methods in comparable plasma sources. Additionally, the electric current, which is calculated using the determined reduced electric field and electron density, is compared with the measured one.
滑行弧等离子体加速器（GAP）是一种很有前途的暖等离子体源，可用于气体转换应用，但缺乏对等离子体动力学的了解。本文利用光学发射光谱（OES）和数值模拟对氮气流（10 slm）下运行的 GAP 滑翔弧等离子体条件进行了表征。同时采用双波长 OES 方法和阿贝尔反演测量图像，空间分辨率为 19.6 μm。本研究采用的碰撞辐射模型包括电子的库仑碰撞。采用迭代法确定等离子体参数。所确定的电场值（最高达 49 Td）和电子密度（最高达 2.5∙10^15 cm-3）与在可比等离子体源中通过不同诊断方法获得的等离子体参数非常吻合。此外，利用确定的还原电场和电子密度计算出的电流也与测量值进行了比较。
{"title":"Characterization of a filamentary discharge ignited in a gliding arc plasmatron operated in nitrogen flow","authors":"Simon Böddeker, Sven Gröger, N. Bibinov, P. Awakowicz","doi":"10.1088/1361-6595/ad473f","DOIUrl":"https://doi.org/10.1088/1361-6595/ad473f","url":null,"abstract":"\u0000 A gliding arc plasmatron (GAP) is a promising warm plasma source for the use in gas conversion applications but lacks an understanding of the plasma dynamics. In this paper, the gliding arc plasma conditions of a GAP operated with nitrogen flow (10 slm) are characterized using optical emission spectroscopy (OES) and numerical simulation. A simultaneously two-wavelength OES method and Abel inversion of the measured images with a spatial resolution of 19.6 μm are applied. The collisional radiative model used in this study includes Coulomb collisions of electrons. An iterative method of plasma parameter determination is applied. The determined values of the electric field up to 49 Td and electron density up to 2.5∙10^15 cm-3 fit well to the plasma parameters received with different diagnostics methods in comparable plasma sources. Additionally, the electric current, which is calculated using the determined reduced electric field and electron density, is compared with the measured one.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"8 32","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141016639","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}
Positive streamer behaviors under repetitive pulses are predominantly dependent on the availability of free electrons. If surface residual electrons stored from previous discharges could be intentionally released and involved into the next discharge, an alternative control freedom is provided apart from voltage waveform tailoring methods that mainly attract or repel gaseous residual charges. Evolutions of repetitively pulsed surface streamers in compressed (0.2 MPa) air were investigated after low-photon-energy pulsed visible (532 nm) and infrared (1064 nm) laser irradiations. Pulse-sequence and temporally resolved diagnostics were implemented to investigate effects of laser parameters (irradiation moment, wavelength, energy) and gas composition. A 2D surface streamer fluid simulation was performed to qualitatively unveil impacts of localized plasma patches. The surface streamer morphology and emission light are significantly and repeatably affected by the laser irradiation before the streamer inception, while, variations totally disappear without the solid surface. The secondary streamer is prolonged accompanied by a higher flashover probability after the pulsed laser irradiation in compressed air. Intriguingly, influences of the infrared laser persist for tens of microseconds before the next voltage pulse. Residual charge dynamics under the laser irradiation are analyzed, where the additional increase of O- 2 of low electron bound energy is emphasized. The laser induced surface trapped electron desorption is achieved through the direct or the step-wise process, dependent on the laser energy and the surface trap state distribution.
{"title":"Repetitively pulsed streamer discharge with laser-induced surface trapped electron desorption to exploit residual charges in situ","authors":"Zheng Zhao, Qiuyu Gao, Xiaoran Li, Haowei Zhang, Luying Bai, Yifei Zhu, Anbang Sun, Jiangtao Li","doi":"10.1088/1361-6595/ad4671","DOIUrl":"https://doi.org/10.1088/1361-6595/ad4671","url":null,"abstract":"\u0000 Positive streamer behaviors under repetitive pulses are predominantly dependent on the availability of free electrons. If surface residual electrons stored from previous discharges could be intentionally released and involved into the next discharge, an alternative control freedom is provided apart from voltage waveform tailoring methods that mainly attract or repel gaseous residual charges. Evolutions of repetitively pulsed surface streamers in compressed (0.2 MPa) air were investigated after low-photon-energy pulsed visible (532 nm) and infrared (1064 nm) laser irradiations. Pulse-sequence and temporally resolved diagnostics were implemented to investigate effects of laser parameters (irradiation moment, wavelength, energy) and gas composition. A 2D surface streamer fluid simulation was performed to qualitatively unveil impacts of localized plasma patches. The surface streamer morphology and emission light are significantly and repeatably affected by the laser irradiation before the streamer inception, while, variations totally disappear without the solid surface. The secondary streamer is prolonged accompanied by a higher flashover probability after the pulsed laser irradiation in compressed air. Intriguingly, influences of the infrared laser persist for tens of microseconds before the next voltage pulse. Residual charge dynamics under the laser irradiation are analyzed, where the additional increase of O- 2 of low electron bound energy is emphasized. The laser induced surface trapped electron desorption is achieved through the direct or the step-wise process, dependent on the laser energy and the surface trap state distribution.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"5 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141020491","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 : 2024-05-02DOI: 10.1088/1361-6595/ad466e
Pawandeep Singh, Avnish K. Pandey, Swati Dahiya, Shantanukumar Karkari
The sheath-edge electric field (E_s) is an important parameter to patch the quasi-neutral pre-sheath and non-neutral sheath regions. The choice of E_s significantly influences the theoretically estimated values of the sheath width, potential, and ion density distribution inside the sheath, as determined by the Poisson equation. The precise nature of E_s has been a persistent subject of investigation, giving rise to the question of whether it should be zero or possess a finite value, as proposed by various authors. In this study, we determine the values of E_s by solving Poisson's equation as a boundary-value problem, utilizing experimentally determined values of sheath radius from a DC-biased hairpin probe. The obtained values of E_s are found to be finite and closely align with the analytical expressions presented by K-U Riemann [J. Phys. D: Appl. Phys. 24 493 (1991)] and Igor D. Kaganovich [Phys. Plasmas 9, 4788 (2002)]. Additionally, the impact of electron-penetrating sheaths and interacting sheaths on the applicability of the hairpin probe in low-pressure plasmas is briefly discussed.
{"title":"Determining Sheath edge electric field around cylindrical pins of a DC biased hairpin resonator probe","authors":"Pawandeep Singh, Avnish K. Pandey, Swati Dahiya, Shantanukumar Karkari","doi":"10.1088/1361-6595/ad466e","DOIUrl":"https://doi.org/10.1088/1361-6595/ad466e","url":null,"abstract":"\u0000 The sheath-edge electric field (E_s) is an important parameter to patch the quasi-neutral pre-sheath and non-neutral sheath regions. The choice of E_s significantly influences the theoretically estimated values of the sheath width, potential, and ion density distribution inside the sheath, as determined by the Poisson equation. The precise nature of E_s has been a persistent subject of investigation, giving rise to the question of whether it should be zero or possess a finite value, as proposed by various authors. In this study, we determine the values of E_s by solving Poisson's equation as a boundary-value problem, utilizing experimentally determined values of sheath radius from a DC-biased hairpin probe. The obtained values of E_s are found to be finite and closely align with the analytical expressions presented by K-U Riemann [J. Phys. D: Appl. Phys. 24 493 (1991)] and Igor D. Kaganovich [Phys. Plasmas 9, 4788 (2002)]. Additionally, the impact of electron-penetrating sheaths and interacting sheaths on the applicability of the hairpin probe in low-pressure plasmas is briefly discussed.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"8 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141018259","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 addressing the substantial greenhouse gas emissions produced by the energy-intensive Haber-Bosch (HB) synthesis, this study investigates the viability of sustainable nitrogen fixation (NF) via low-temperature plasma systems energized by renewable sources. Utilizing vibrational coherent anti-Stokes Raman scattering (CARS) as a diagnostic tool, we probed the nitrogen rovibrational temperature and population dynamics within a DC glow discharge in atmospheric air, a setting with considerable promise for eco-friendly fertilizer production. Besides, density for atomic N, O, and NO molecule was quantified by laser-induced fluorescence (LIF) or two-photon absorbed lase-induced fluorescence (TALIF) methods. Our findings reveal a quasi-equilibrium between rotational and vibrational energy states in the DC glow discharge environment, reaching an approximate value of 3500 K at the discharge core. The discharge parameters, discharge current, air flow rate, and discharge gap influence the rovibrational temperature, density distribution of species of interest, and the NF energy cost. However, the influences induced by these parameters are of limitations. Further analysis implies that the high gas temperature and its induced vibrational-rotational (V-R) and vibrational-translational (V-T) energy exchange are mainly responsible for the non-ideal NF energy cost.
{"title":"Assessing the efficacy of an atmospheric air DC glow discharge system for sustainable nitrogen fixation: A vibrational coherent anti-Stokes Raman scattering study","authors":"Junjie Qiao, Qi Yang, Da-Zhi Wang, Xuekai Pei, Qing Xiong","doi":"10.1088/1361-6595/ad42d1","DOIUrl":"https://doi.org/10.1088/1361-6595/ad42d1","url":null,"abstract":"\u0000 In addressing the substantial greenhouse gas emissions produced by the energy-intensive Haber-Bosch (HB) synthesis, this study investigates the viability of sustainable nitrogen fixation (NF) via low-temperature plasma systems energized by renewable sources. Utilizing vibrational coherent anti-Stokes Raman scattering (CARS) as a diagnostic tool, we probed the nitrogen rovibrational temperature and population dynamics within a DC glow discharge in atmospheric air, a setting with considerable promise for eco-friendly fertilizer production. Besides, density for atomic N, O, and NO molecule was quantified by laser-induced fluorescence (LIF) or two-photon absorbed lase-induced fluorescence (TALIF) methods. Our findings reveal a quasi-equilibrium between rotational and vibrational energy states in the DC glow discharge environment, reaching an approximate value of 3500 K at the discharge core. The discharge parameters, discharge current, air flow rate, and discharge gap influence the rovibrational temperature, density distribution of species of interest, and the NF energy cost. However, the influences induced by these parameters are of limitations. Further analysis implies that the high gas temperature and its induced vibrational-rotational (V-R) and vibrational-translational (V-T) energy exchange are mainly responsible for the non-ideal NF energy cost.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"30 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140663328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-24DOI: 10.1088/1361-6595/ad42d0
Dante Filice, Sylvain Coulombe
Sub-breakdown radiofrequency (RF) discharges enabled by a nanosecond (ns) pulse ignition source are studied at atmospheric pressure in a range of gas mixtures from completely inert (in Ar) to completely reactive (in CO2). An electrical characterisation of the continuous wave (CW) RF discharge (13.56MHz) is performed to determine plasma impedance and plasma power dissipation. Two different measurement methods to electrically characterize the system are described and compared. One method uses in-situ measurements of discharge parameters (voltage, current and the phase angle), and the other method performs ex-situ measurements of the load circuit using a vector network analyser. It was found that RF plasma power deposition depended on the applied RF power as well as the gas mixture composition. Using the in-situ voltage, current and phase angle measurements, plasma power deposition was calculated to be as much as 85% and 76% of the applied RF power for the pure Ar and pure CO2 cases, respectively. A preliminary qualitative assessment of the plasma composition was performed by optical emission spectroscopy, and CO2 conversion by mass spectrometry. CO2 to CO conversions of 11.2% and 5.5% in a 20:80 (CO2:Ar) mixture and in 100% CO2, respectively, were observed. This study demonstrates a RF plasma source for gas conversion applications at atmospheric pressure in a completely reactive gas.
研究了在大气压力下，从完全惰性（在氩气中）到完全反应性（在二氧化碳中）的一系列气体混合物中，由纳秒（ns）脉冲点火源产生的次击穿射频（RF）放电。对连续波（CW）射频放电（13.56MHz）进行了电学表征，以确定等离子体阻抗和等离子体功率耗散。文中介绍了两种不同的测量方法，并对其进行了比较。一种方法是对放电参数（电压、电流和相位角）进行现场测量，另一种方法是使用矢量网络分析仪对负载电路进行现场测量。结果发现，射频等离子体功率沉积取决于应用的射频功率和气体混合物成分。通过原位电压、电流和相位角测量，计算出纯 Ar 和纯 CO2 的等离子功率沉积分别为应用射频功率的 85% 和 76%。通过光学发射光谱对等离子体的成分进行了初步定性评估，并通过质谱法对二氧化碳的转化率进行了评估。在 20:80（CO2:Ar）混合物和 100% CO2 中，CO2 对 CO 的转化率分别为 11.2% 和 5.5%。这项研究展示了一种射频等离子体源，可用于在常压下完全反应气体中的气体转化应用。
{"title":"Combined ns pulsed-RF excitation and impedance matching considerations for the production of moderate E/n atmospheric pressure discharges for gas conversion","authors":"Dante Filice, Sylvain Coulombe","doi":"10.1088/1361-6595/ad42d0","DOIUrl":"https://doi.org/10.1088/1361-6595/ad42d0","url":null,"abstract":"\u0000 Sub-breakdown radiofrequency (RF) discharges enabled by a nanosecond (ns) pulse ignition source are studied at atmospheric pressure in a range of gas mixtures from completely inert (in Ar) to completely reactive (in CO2). An electrical characterisation of the continuous wave (CW) RF discharge (13.56MHz) is performed to determine plasma impedance and plasma power dissipation. Two different measurement methods to electrically characterize the system are described and compared. One method uses in-situ measurements of discharge parameters (voltage, current and the phase angle), and the other method performs ex-situ measurements of the load circuit using a vector network analyser. It was found that RF plasma power deposition depended on the applied RF power as well as the gas mixture composition. Using the in-situ voltage, current and phase angle measurements, plasma power deposition was calculated to be as much as 85% and 76% of the applied RF power for the pure Ar and pure CO2 cases, respectively. A preliminary qualitative assessment of the plasma composition was performed by optical emission spectroscopy, and CO2 conversion by mass spectrometry. CO2 to CO conversions of 11.2% and 5.5% in a 20:80 (CO2:Ar) mixture and in 100% CO2, respectively, were observed. This study demonstrates a RF plasma source for gas conversion applications at atmospheric pressure in a completely reactive gas.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"10 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140665517","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}
Electric field measurement using electric-field-induced second-harmonic generation (E-FISHG) has attracted attention because of its non-invasiveness and high spatiotemporal resolution. In the electric field measurement by the E-FISHG method, the applied electric-field profile along the laser path outside the focal spot affects the SHG signal. We have proposed a method of calibrating and inferring the applied electric-field profile from the SHG distribution along the laser path. In our previous research, the successful inference of a relatively simple electric-field profile from a series of SHG signals was demonstrated. To measure more complex electric-field profiles, we apply our method to three cases of electric-field profiles: (1) the profile with different sharpness, (2) the profile with two peaks, and (3) the profile with noise superimposed on the SHG signal. The applied electric-field distribution can be inferred within 10% error by adequately choosing the confocal parameter. We also provide guidelines for the required signal acquisition region and measurement pitch when the approximate shape of the applied electric field is known, which are important for actual measurement.
{"title":"Adequate laser focusing and signal acquisition conditions for 3D measurement of electric-field distribution by the E-FISHG method","authors":"Masataka Sogame, Shin Nakamura, Masahiro Sato, Takashi Fujii, Akiko Kumada","doi":"10.1088/1361-6595/ad4237","DOIUrl":"https://doi.org/10.1088/1361-6595/ad4237","url":null,"abstract":"\u0000 Electric field measurement using electric-field-induced second-harmonic generation (E-FISHG) has attracted attention because of its non-invasiveness and high spatiotemporal resolution. In the electric field measurement by the E-FISHG method, the applied electric-field profile along the laser path outside the focal spot affects the SHG signal. We have proposed a method of calibrating and inferring the applied electric-field profile from the SHG distribution along the laser path. In our previous research, the successful inference of a relatively simple electric-field profile from a series of SHG signals was demonstrated. To measure more complex electric-field profiles, we apply our method to three cases of electric-field profiles: (1) the profile with different sharpness, (2) the profile with two peaks, and (3) the profile with noise superimposed on the SHG signal. The applied electric-field distribution can be inferred within 10% error by adequately choosing the confocal parameter. We also provide guidelines for the required signal acquisition region and measurement pitch when the approximate shape of the applied electric field is known, which are important for actual measurement.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"121 28","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140669314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1088/1361-6595/ad4238
Ximing Zhu, Lu Wang, Yan-Fei Wang, Yang Wang, Da-Ren Yu, K. Bartschat
The active-particle number density is a key parameter for plasma material processing, space propulsion, and plasma-assisted combustion.The traditional actinometry method focuses on measuring the density of the atoms in the ground state, but there is a lack of an effective optical emission spectroscopy method to measure intra-shell excited-state densities. The latter atoms have chemical selectivity and higher energy, and they can easily change the material morphology as well as the ionization and combustion paths. In this work, we present a novel state-resolved actinometry (SRA) method, supported by a krypton line-ratio method for the electron temperature and density, to measure the number densities of nitrogen atoms in the ground and intra-shell excited states. The SRA method is based on a collisional-radiative model, considering the kinetics of atomic nitrogen and krypton including their excited states. The densities measured by our method are compared with those obtained from a dissociative model in a miniature electron cyclotron resonance plasma (ECR) source. Furthermore, the saturation effect, in which the electron density remains constant due to the microwave propagation in an ECR plasma once the power reaches a certain value, is used to verify the electron density measured by the line-ratio method. An ionization balance model is also presented to examine the measured electron temperature. All the values obtained with the different methods are in good agreement with each other, and hence a set of verified rate coefficient data used in our method can be provided. A novel concept, the "excited-state system", is presented to quickly build an optical diagnostic method based on the analysis of quantum number propensity and selection rules.
{"title":"A novel state-resolved actinometry method to determine the nitrogen atom number density in the ground state and intra-shell excited states in low-pressure electron cyclotron resonance plasmas","authors":"Ximing Zhu, Lu Wang, Yan-Fei Wang, Yang Wang, Da-Ren Yu, K. Bartschat","doi":"10.1088/1361-6595/ad4238","DOIUrl":"https://doi.org/10.1088/1361-6595/ad4238","url":null,"abstract":"\u0000 The active-particle number density is a key parameter for plasma material processing, space propulsion, and plasma-assisted combustion.The traditional actinometry method focuses on measuring the density of the atoms in the ground state, but there is a lack of an effective optical emission spectroscopy method to measure intra-shell excited-state densities. The latter atoms have chemical selectivity and higher energy, and they can easily change the material morphology as well as the ionization and combustion paths. In this work, we present a novel state-resolved actinometry (SRA) method, supported by a krypton line-ratio method for the electron temperature and density, to measure the number densities of nitrogen atoms in the ground and intra-shell excited states. The SRA method is based on a collisional-radiative model, considering the kinetics of atomic nitrogen and krypton including their excited states. The densities measured by our method are compared with those obtained from a dissociative model in a miniature electron cyclotron resonance plasma (ECR) source. Furthermore, the saturation effect, in which the electron density remains constant due to the microwave propagation in an ECR plasma once the power reaches a certain value, is used to verify the electron density measured by the line-ratio method. An ionization balance model is also presented to examine the measured electron temperature. All the values obtained with the different methods are in good agreement with each other, and hence a set of verified rate coefficient data used in our method can be provided. A novel concept, the \"excited-state system\", is presented to quickly build an optical diagnostic method based on the analysis of quantum number propensity and selection rules.","PeriodicalId":508056,"journal":{"name":"Plasma Sources Science and Technology","volume":"28 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140665843","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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