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1.
Tetsutarou OISHI Naoko ASHIKAWA Federico NESPOLI Suguru MASUZAKI Mamoru SHOJI Eric P GILSON Robert LUNSFORD Shigeru MORITA Motoshi GOTO Yasuko KAWAMOTO Chihiro SUZUKI Zhen SUN Alex NAGY David A GATES Tomohiro MORISAKI 《等离子体科学和技术》2021,23(8):6-17
An impurity powder dropper was installed in the 21 st campaign of the Large Helical Device experiment(Oct. 2019–Feb. 2020) under a collaboration between the National Institute for Fusion Science and the Princeton Plasma Physics Laboratory for the purposes of real-time wall conditioning and edge plasma control. In order to assess the effective injection of the impurity powders,spectroscopic diagnostics were applied to observe line emission from the injected impurity. Thus,extreme-ultraviolet(EUV) and vacuum-ultraviolet(VUV) emission spectra were analyzed to summarize observable impurity lines with B and BN powder injection. Emission lines released from B and N ions were identified in the EUV wavelength range of 5–300 ? measured using two grazing incidence flat-field EUV spectrometers and in the VUV wavelength range of 300–2400 ? measured using three normal incidence 20 cm VUV spectrometers. BI–BV and NIII–NVII emission lines were identified in the discharges with the B and BN powder injection, respectively. Useful B and N emission lines which have large intensities and are isolated from other lines were successfully identified as follows: BI(1825.89, 1826.40) ?(blended), BII 1362.46 ?, BIII(677.00, 677.14,677.16) ?(blended), BIV 60.31 ?, BV 48.59 ?, NIII(989.79, 991.51, 991.58) ?(blended), NIV765.15 ?, NV(209.27, 209.31) ?(blended), NVI 1896.80 ?, and NVII 24.78 ?. Applications of the line identifications to the advanced spectroscopic diagnostics were demonstrated, such as the vertical profile measurements for the BV and NVII lines using a space-resolved EUV spectrometer and the ion temperature measurement for the BII line using a normal incidence 3 m VUV spectrometer. 相似文献
2.
HL-2A tokamak with two close divertors has been operated since 2003. In the experimental campaign of 2004 the divertor configuration has been successfully formed and the sillconization as a wall conditioning has been firstly done in this device. The divertor configuration can be reconstructed by the CFc code. Impurity behavior has been investigated during the experiment with divertor configuration and wall conditioning. The reduction of impurity is clear under both conditions of divertor configuration and siliconization. 相似文献
3.
Hongming ZHANG 《等离子体科学和技术》2020,22(8):84001-084001
The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV) range, as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST). The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas. Therefore, in this study, a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST. One Seya-Namioka VUV spectrometer(McPherson 234/302) is used in the system, equipped with a concave-corrected holographic grating with groove density of 600 grooves mm~(–1). Impurity line emissions can be observed in the wavelength range ofλ=50–700 nm, covering VUV, near ultraviolet and visible ranges. The observed vertical range is Z=-350–350 mm. The minimum sampling time can be set to 5 ms under full vertical binning(FVB) mode. VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign. Impurity spectra are identified for several impurity species, i.e., lithium(Li), carbon(C), oxygen(O), and iron(Fe). Several candidates for tungsten(W) lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines. Time evolutions of impurity carbon emissions of CII at 134.5 nm and CIII at97.7 nm are analyzed to prove the system capability of time-resolved measurement. The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST. 相似文献
4.
《等离子体科学和技术》2024,26(8)
A vacuum ultraviolet(VUV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak(EAST).In this study,wavelength calibration for the VUV spectroscopy is achieved utilizing a zinc lamp.The grating angle and charge-coupled device(CCD)position are carefully calibrated for different wavelength positions.The wavelength calibration of the VUV spectroscopy is crucial for improving the accuracy of impurity spectral data,and is required to identify more impurity spectral lines for impurity transport research.Impurity spectra of EAST plasmas have also been obtained in the wavelength range of 50-300 nm with relatively high spectral resolution.It is found that the impurity emissions in the edge region are still dominated by low-Z impurities,such as carbon,oxygen,and nitrogen,albeit with the application of full-tungsten divertors on the EAST tokamak. 相似文献
5.
Huajian JI; Hongming ZHANG; Bo LYU; Cheonho BAE; Liang HE; Zichao LIN; Xianghui YIN; Yongcai SHEN; Shuyu DAI 《等离子体科学和技术》2024,26(8):085105-1-085105-7
A vacuum ultraviolet (VUV) spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak (EAST). In this study, wavelength calibration for the VUV spectroscopy is achieved utilizing a zinc lamp. The grating angle and charge-coupled device (CCD) position are carefully calibrated for different wavelength positions. The wavelength calibration of the VUV spectroscopy is crucial for improving the accuracy of impurity spectral data, and is required to identify more impurity spectral lines for impurity transport research. Impurity spectra of EAST plasmas have also been obtained in the wavelength range of 50–300 nm with relatively high spectral resolution. It is found that the impurity emissions in the edge region are still dominated by low-Z impurities, such as carbon, oxygen, and nitrogen, albeit with the application of full-tungsten divertors on the EAST tokamak. 相似文献
6.
Post-mortem methods cannot fulfill the requirement of monitoring the lifetime of the plasma facing components(PFC) and measuring the tritium inventory for the safety evaluation.Laserinduced breakdown spectroscopy(LIBS) is proposed as a promising method for the in situ study of fuel retention and impurity deposition in a tokamak.In this study,an in situ LIBS system was successfully established on EAST to investigate fuel retention and impurity deposition on the first wall without the need of removal tiles between plasma discharges.Spectral lines of D,H and impurities(Mo,Li,Si,...) in laser-induced plasma were observed and identified within the wavelength range of 500-700 nm.Qualitative measurements such as thickness of the deposition layers,element depth profile and fuel retention on the wall are obtained by means of in situ LIBS.The results demonstrated the potential applications of LIBS for in situ characterization of fuel retention and co-deposition on the first wall of EAST. 相似文献
7.
M. B. CHOWDHURI R. MANCHANDA J. GHOSH S. B. BHATT Ajai KUMAR B. K. DAS K. A. JADEJA P. A. RAIJADA Manoj KUMAR S. BANERJEE Nilam RAMAIYA Aniruddh MALI Ketan M. PATEL Vinay KUMAR P. VASU R. BHATTACHARYAY R. L. TANNA Y. Shankara JOISA P. K. ATREY C. V. S. RAO D. Chenna REDDY P. K. CHATTOPADHYAY R. JHA Y. C. SAXENA Aditya team 《等离子体科学和技术》2013,15(2):123-128
Lithiumization of the vacuum vessel wall of the Aditya tokamak using a lithium rod exposed to glow discharge cleaning plasma has been done to understand its effect on plasma performance. After the Li-coating, an increment of ～100 eV in plasma electron temperature has been observed in most of the discharges compared to discharges without Li coating, and the shot reproducibility is considerably improved. Detailed studies of impurity behaviour and hydrogen recycling are made in the Li coated discharges by observing spectral lines of hydrogen, carbon, and oxygen in the visible region using optical fiber, an interference filter, and PMT based systems. A large reduction in O I signal (up to ～ 40% to 50%) and a 20% to 30% decrease of H α signal indicate significant reduction of wall recycling. Furthermore, VUV emissions from O V and Fe XV monitored by a grazing incidence monochromator also show the reduction. Lower Fe XV emission indicates the declined impurity penetration to the core plasma in the Li coated discharges. Significant increase of the particle and energy confinement times and the reduction of Z eff of the plasma certainly indicate the improved plasma parameters in the Aditya tokamak after lithium wall conditioning. 相似文献
8.
Shigeru MORITA Motoshi GOTO Sadatsugu MUTO Ryuji KATAI Hisamichi YAMAZAKI Hideaki NOZATO Atsushi IWAMAE Makoto ATAKE Takashi FUJIMOTO Atsushi SAKAUE Hiroaki NISHIMURA Ikuya SAKURAI Chiho MATSUMOTO Akihiro FURUZAWA Yuzuru TAWARA Mitsutoshi ARAMAKI Yuji OKUMURA Koichi SASAKI龚先祖 李建刚万宝年 崔正英 《等离子体科学和技术》2006,8(1):55-60
Spectroscopic diagnostics have been extensively developed for studies of impurity and neutral particle transports at core and edge plasmas in LHD. Diagnostics of core plasmas are similar to a tokamak case, i.e., Zeff from visible bremsstrahlung, K-x-ray measurements from xray spectroscopy using Si（Li） detectors and a compact crystal spectrometer, and high-Z impurity diagnostics from VUV spectroscopy using a flat-field EUV spectrometer. A combination of impurity pellet injection and visible bremsstrahlung is an active tool for determination of the diffusion coeffici＇ent D and convective velocity V. Using this tool the spatial structures of D and V are obtained and discussed with a neoclassical effect. On the other hand, the spectroscopic method for edge diagnostics is considerably different from the tokamak case because of the existence of a thick ergodic layer in addition to the z-points necessarily included into the diagnostic chord view. In order to break this negative situation, Zeeman and polarization spectroscopy are adopted to LHD edge plasmas. As a result, 2-dimensional emission contours of HeI and Ha are successfully obtained. Laser absorption spectroscopy is tried to measure hydrogen neutrals directly. Radial profiles of edge impurities are also measured with a mirror-assembled 3 m VUV spectrometer. Recent results of and progress in LHD spectroscopy are briefly reviewed. 相似文献
9.
We have studied laser-produced plasma based on mass-limited thin-film Gd targets for beyond the current extreme ultraviolet (EUV) light source of 13.5 nm wavelength based on tin. The influences of the laser intensity on the emission spectra centered around 6.7 nm from thin-film Gd targets were first investigated. It is found that the conversion efficiency of the produced plasma is saturated when the laser intensity goes beyond 2 × 1011 W cm−2. We have systematically compared the emission spectra of the laser-produced plasma with the changes in the thicknesses of the thin-film Gd targets. It is proved that a minimum-mass target with a thickness of 400 nm is sufficient to provide the maximum conversion efficiency, which also implies that this thickness is the ablation depth for the targets. These findings should be helpful in the exploration of next-generation EUV sources, as the thin-film Gd targets will reduce the debris during the plasma generation process compared with the bulk targets. 相似文献
10.
The steady fusion plasma operation is constrained by tungsten(W) material sputtering issue in the EAST tokamak. In this work, the suppression of W sputtering source has been studied by advanced wall conditionings. It is also concluded that the W sputtering yield becomes more with increasing carbon(C) content in the main deuterium(D) plasma. In EAST, the integrated use of discharge cleanings and lithium(Li) coating has positive effects on the suppression of W sputtering source. In the plasma recovery experiments, it is suggested that the W intensity is reduced by approximately 60% with the help of ～35 h Ion Cyclotron Radio Frequency Discharge Cleaning(ICRF-DC) and ～40 g Li coating after vacuum failure. The first wall covered by Li film could be relieved from the bombardment of energetic particles, and the impurity in the vessel would be removed through the particle induced desorption and isotope exchange during the discharge cleanings. In general, the sputtering yield of W would decrease from the source, on the bias of the improvement of wall condition and the mitigation of plasmawall interaction process. It lays important base of the achievement of high-parameter and longpulse plasma operation in EAST. The experiences also would be constructive for us to promote the understanding of relevant physics and basis towards the ITER-like condition. 相似文献
11.
The high magnetic field helicon experiment system is a helicon wave plasma(HWP)source device in a high axial magnetic field(B_0)developed for plasma–wall interactions studies for fusion reactors.This HWP was realized at low pressure(5?×?10~(-3)?-?10 Pa)and a RF(radio frequency,13.56 MHz)power(maximum power of 2 k W)using an internal right helical antenna(5 cm in diameter by 18 cm long)with a maximum B_0of 6300 G.Ar HWP with electron density~10~(18)–10~(20)m~(-3)and electron temperature~4–7 e V was produced at high B_0 of 5100 G,with an RF power of 1500 W.Maximum Ar~+ion flux of 7.8?×?10~(23)m~(-2)s~(-1)with a bright blue core plasma was obtained at a high B_0 of 2700 G and an RF power of 1500 W without bias.Plasma energy and mass spectrometer studies indicate that Ar~+ion-beams of 40.1 eV are formed,which are supersonic(~3.1c_s).The effect of Ar HWP discharge cleaning on the wall conditioning are investigated by using the mass spectrometry.And the consequent plasma parameters will result in favorable wall conditioning with a removal rate of 1.1?×?10~(24)N_2/m~2 h. 相似文献
12.
Plasma radiation characteristics in EAST argon(Ar) gas and neon(Ne) gas seeding experiments are studied.The radiation profiles reconstructed from the fast bolometer measurement data by tomography method are compared with the ones got from the simulation program based on corona model.And the simulation results coincide roughly with the experimental data.For Ar seeding discharges,the substantial enhanced radiations can be generally observed in the edge areas at normalized radius ρ_(pol)~0.7–0.9,while the enhanced regions are more outer for Ne seeding discharges.The influence of seeded Ar gas on the core radiation is related to the injected position.In discharges with LSN divertor configuration,the Ar ions can permeate into the core region more easily when being injected from the opposite upper divertor ports.In USN divertor configuration,the W impurity sputtered from the upper divertor target plates are observed to be an important contributor to the increase of the core radiation no matter impurity seeding from any ports.The maximum radiated power fractions f_(rad)(P_(rad)/P_(heat)) about 60%–70% have been achieved in the recent EAST experimental campaign in 2015–2016. 相似文献
13.
Al-doped ZnO (AZO) is considered as an alternative to transparent conductive oxide materials. Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF4/Ar ratio of 50:50 sccm. Regardless of the ratio of CF4 to Ar, the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication. 相似文献
14.
A new type of AC PDP (alternating current plasma display panel) cell with a fiveelectrode structure is developed to improve the luminous efficiency of AC PDP, The discharge efficiency of this new cell structure is investigated by a 2D fluid simulation. Continuity equations and flux density equations for charged particles and excited atoms, energy balance equation for electrons are included in the model. The discharge gas is He 5%Xe. The reactions of ionization, excitation, recombination, and radiation are taken into account. The vacuum ultraviolet radiation efficiency of the five-electrode cell structure is about 20% higher than that of a conventional three-electrode cell structure. 相似文献
15.
An electromagnetic calculation and the parameters of the magnet system of the magnetically confined plasma rocket were established. By using ANSYS code, it was found that the leakage rate depends on the current intensity of the magnet and the change of the magnet position. 相似文献
16.
Min WANG 《等离子体科学和技术》2022,24(1):15101
Impurity seeding has been found effective for divertor detachment operations and the seeding location plays a key role in this process. In this work, we use the fluid code SOLPS-ITER to study the influence of seeding locations on divertor and scrape-off layer (D-SOL) plasmas in Experimental Advanced Superconducting Tokamak (EAST) with neon seeding. Simulation results indicate that the neon is a highly effective impurity in mitigating the heat flux and electron temperature peaks on the target of the divertor and achieving the partial detachment on both inner and outer targets. Further, by comparing results of the seeding at the private-flux region (PFR) plate (called 'TP' location) and the outer target (called 'XP' location), we find that the impurity density and power radiation for TP case are higher in core and upstream regions and lower in the divertor region than that for seeding at the XP, and the difference becomes more and more obvious as the seeding rate increases. It clearly demonstrates that the seeding at the XP location is more appropriate than at the TP location, especially in high seeding rate conditions. 相似文献
17.
Plasma sterilization is a new generation of high-tech sterilization method that is fast, safe, and pollution free. It is widely used in medical, food, and environmental protection fields. Home air sterilization is an emerging field of plasma application, which puts higher requirements on the miniaturization, operational stability, and operating cost of plasma device. In this study, a novel magnetically driven rotating gliding arc (MDRGA) discharge device was used to sterilize Lactobacillus fermentation. Compared with the traditional gas-driven gliding arc, this device has a simple structure and a more stable gliding arc. Simulation using COMSOL Multiphysics showed that adding permanent magnets can form a stable magnetic field, which is conducive to the formation of gliding arcs. Experiments on the discharge performance, ozone concentration, and sterilization effect were conducted using different power supply parameters. The results revealed that the MDRGA process can be divided into three stages: starting, gliding, and extinguishing. Appropriate voltage was the key factor for stable arc gliding, and both high and low voltages were not conducive to stable arc gliding and ozone production. In this experimental setup, the sterilization effect was the best at 6.6 kV. A high modulation duty ratio was beneficial for achieving stable arc gliding. However, when the duty ratio exceeded a certain value, the improvement in the sterilization effect was slow. Therefore, considering the sterilization effect and energy factors comprehensively, we chose 80% as the optimal modulation duty ratio for this experimental device. 相似文献
18.
A grazing incidence flat-field spectrograph using a concave grating was constructed to measure extreme ultraviolet (EUV) emission from a CO 2 laser-produced tin plasma throughout the wavelength region of 5 nm to 20 nm for lithography. Spectral efficiency of the EUV emission around 13.5 nm from plate, cavity, and thin foil tin targets was studied. By translating the focusing lens along the laser axis, the dependence of EUV spectra on the amount of defocus was investigated. The results showed that the spectral efficiency was higher for the cavity target in comparison to the plate or foil target, while it decreased with an increase in the defocus distance. The source’s spectra and the EUV emission intensity normalized to the incident pulse energy at 45 from the target normal were characterized for the in-band (2% of bandwidth) region as a function of laser energy spanning from 46 mJ to 600 mJ for the pure tin plate target. The energy normalized EUV emission was found to increase with the increasing incident pulse energy. It reached the optimum value for the laser energy of around 343 mJ, after which it dropped rapidly. 相似文献
19.
20.
An edge Lyman-alpha-based beam emission spectroscopy (LyBES) diagnostic, using a heating NBI (neutral beam injection) system, is currently under development on the HL-2A tokamak. The 20-channel edge LyBES, which is intended to measure the density fluctuation in plasma edge (from R = 1960 mm to R = 2026 mm) with an improved spatial resolution of 3.3 mm, is a complement to the existing conventional beam emission spectroscopy (BES) diagnostic. In this article, we introduce the progress of LyBES diagnostic, including the collection optics, the monochromator, and the detector system. The reflectance of the collection mirrors is measured to be ~82% at 122 nm, and the aberration geometrical radius of the collection optics is tested to be ~150 μm in the aimed area. The linear dispersion of the LyBES monochromator is designed to be ~0.09 nm mm−1. The bandwidth of the detector system with the 5×107 V A−1 preamplifier gain is measured to be ~280 kHz, and the peak-to-peak noise of the detector system is tested to be ~16 mV. The finalized design, components development and testing of the LyBES diagnostic have been completed at present, and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2A campaign. 相似文献