scholarly journals Observation of Quasi-Continuum Line Emission from F[CLC]e[/CLC] [CSC]vii[/CSC] to F[CLC]e[/CLC] [CSC]x[/CSC] in the Extreme-Ultraviolet Region below 140 Å

1999 ◽  
Vol 519 (2) ◽  
pp. L185-L188 ◽  
Author(s):  
P. Beiersdorfer ◽  
J. K. Lepson ◽  
G. V. Brown ◽  
S. B. Utter ◽  
S. M. Kahn ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Line Emission ◽  
Ultraviolet Region

Images of Impurity Line Emission in the Extreme Ultraviolet Region From the Large Helical Device With an Edge Stochastic Magnetic Field Layer

2014 ◽  
Vol 42 (10) ◽  
pp. 2542-2543 ◽  
Author(s):  
Shigeru Morita ◽  
Erhui Wang ◽  
Chunfeng Dong ◽  
Tetsutarou Oishi ◽  
Motoshi Goto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Extreme Ultraviolet ◽  
Line Emission ◽  
Ultraviolet Region ◽  
Field Layer ◽  
Stochastic Magnetic Field

Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Germán Vogel ◽  
Hongming Zhang ◽  
Yongcai Shen ◽  
Shuyu Dai ◽  
Youwen Sun ◽  
...  
Keyword(s):  
Inner Core ◽  
Extreme Ultraviolet ◽  
Transport Coefficients ◽  
Three Dimensional ◽  
Line Emission ◽  
Core Region ◽  
Emission Mitigation ◽  
One Dimensional ◽  
Impurity Transport ◽  
Transport Code

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

Effect of energetic electron and proton bombardment on the reflectance of silicon-carbide mirrors in the extreme-ultraviolet region

1994 ◽  
Vol 33 (25) ◽  
pp. 5902 ◽  
Author(s):  
G. E. Holland ◽  
J. F. Seely ◽  
R. P. McCoy ◽  
K. F. Dymond ◽  
C. Rollins ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Extreme Ultraviolet ◽  
Energetic Electron ◽  
Ultraviolet Region ◽  
Proton Bombardment

scholarly journals Phase-matched four-wave mixing in the extreme ultraviolet region

2018 ◽  
Vol 124 (1) ◽  
pp. 015901 ◽  
Author(s):  
Khoa Anh Tran ◽  
Khuong Ba Dinh ◽  
Peter Hannaford ◽  
Lap Van Dao
Keyword(s):  
Extreme Ultraviolet ◽  
Four Wave Mixing ◽  
Ultraviolet Region ◽  
Wave Mixing

Wave-Front Quality Analysis of Three-Dimension Pinhole Vector Diffractional in Extreme Ultraviolet Region

2010 ◽  
Vol 30 (10) ◽  
pp. 2849-2854 ◽  
Author(s):  
卢增雄 Lu Zengxiong ◽  
金春水 Jin Chunshui ◽  
张立超 Zhang Lichao ◽  
王丽萍 Wang Liping
Keyword(s):  
Wave Front ◽  
Extreme Ultraviolet ◽  
Quality Analysis ◽  
Ultraviolet Region ◽  
Three Dimension

scholarly journals Dissecting the EUV Spectrum of Capella

1996 ◽  
Vol 152 ◽  
pp. 105-112 ◽  
Author(s):  
Nancy S. Brickhouse
Keyword(s):  
Extreme Ultraviolet ◽  
Emission Measure ◽  
Continuous Distribution ◽  
Line Emission ◽  
Local Maximum ◽  
Abundance Ratio ◽  
Emission Lines ◽  
Cool Star ◽  
The Individual ◽  
The Continuum

Extreme ultraviolet spectra of Capella, obtained at various orbital phases over the past two years by the EUVE satellite, show strong emission lines from a continuous distribution of temperatures (~ 105 − 107.3 K). In addition to the strong He II λ303.8, the spectra are dominated by emission lines of highly ionized iron. Strong lines of Fe IX, XV, XVI, and XVIII–XXIV are used to construct emission measure distributions for the individual pointings, which show several striking features, including a minimum near 106 K and a local maximum at 106.8 K. Furthermore, intensities of the highest temperature lines (Te > 107 K) show variations (factors of 2–3) at different orbital phases, while the lower temperature Fe lines show variations of about 30% or less. The low variability of most of the strong low temperature features motivates a detailed analysis of the summed spectrum. With ~ 280 ks of total exposure time, we have measured over 200 emission features with S/N ≥ 3.0 in the summed spectrum. We report here initial results from the analysis of this spectrum. We can now identify lines of Fe VIII and X–XIV, as well as a number of electron density and abundance diagnostic lines.We also report here the first direct measurement of the continuum flux around ~ 100 Å in a cool star atmosphere with EUVE. The continuum flux can be predicted from the emission measure model based on Fe line emission, and demonstrates that the Fe/H abundance ratio is close to the solar photospheric value.

Upgrade of beamline BL08B at Taiwan Light Source from a photon-BPM to a double-grating SGM beamline

2015 ◽  
Vol 22 (5) ◽  
pp. 1312-1318 ◽  
Author(s):  
Jih-Young Yuh ◽  
Shan-Wei Lin ◽  
Liang-Jen Huang ◽  
Hok-Sum Fung ◽  
Long-Life Lee ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Solar Physics ◽  
Emission Spectra ◽  
Ultraviolet Region ◽  
Extreme Ultraviolet Lithography ◽  
Beam Position ◽  
Ultraviolet Lithography ◽  
X Ray ◽  
Nano Fabrication ◽  
Grating Monochromator

During the last 20 years, beamline BL08B has been upgraded step by step from a photon beam-position monitor (BPM) to a testing beamline and a single-grating beamline that enables experiments to record X-ray photo-emission spectra (XPS) and X-ray absorption spectra (XAS) for research in solar physics, organic semiconductor materials and spinel oxides, with soft X-ray photon energies in the range 300–1000 eV. Demands for photon energy to extend to the extreme ultraviolet region for applications in nano-fabrication and topological thin films are increasing. The basic spherical-grating monochromator beamline was again upgraded by adding a second grating that delivers photons of energy from 80 to 420 eV. Four end-stations were designed for experiments with XPS, XAS, interstellar photoprocess systems (IPS) and extreme-ultraviolet lithography (EUVL) in the scheduled beam time. The data from these experiments show a large count rate in core levels probed and excellent statistics on background normalization in theL-edge adsorption spectrum.

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