Experimental and Theoretical Evaluation of Density‐sensitive N<scp>vi</scp>, Ar<scp>xiv</scp>, and Fe<scp>xxii</scp>Line Ratios

Chen, H.; Beiersdörfer, P.; Heeter, L. A.; Liedahl, D. A.; Naranjo-Rivera, K L; Träbert, E.; Gu, M. F.; Lepson, J. K.

doi:10.1086/421987

Cited by 54 publications

(60 citation statements)

References 29 publications

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“…1, the electron density n e = 5.6 × 10 10 cm −3 is derived. This result is consistent with value 6.0×10 10 cm −3 recently diagnosed by Chen et al [34] using triplet line intensity ratio of He-like N ion. Table 2 shows the diagnosed electron densities of the EBIT-II plasma from different line ratios.…”

Section: Resultssupporting

confidence: 93%

Electron density diagnostic potential of Ar XIV soft X-ray emission lines

Liang

Zhao

Zeng

et al. 2006

Journal of Quantitative Spectroscopy and Radiative Transfer

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Theoretical electron density-sensitive line ratios R 1 − R 6 of Ar XIV soft X-ray emission lines are presented. We found that these line ratios are sensitive to electron density n e , and the ratio R 1 is insensitive to electron temperature T e . Recent work has shown that accurate atomic data, such as electron impact excitation rates, is very important for reliable determination of the electron density of laboratory and astrophysical plasmas. Present work indicates that the maximum discrepancy of line ratios introduced from different atomic data calculated with distorted wave and R-matrix approximations, is up to 18% in the range of n e = 10 9−13 cm −3 . By comparison of these line ratios with experiment results carried out in electron beam ion trap (EBIT-II), electron density of the laboratory plasma is diagnosed, and a consistent result is obtained from R 1 , R 2 and R 3 . Our result is in agreement with that diagnosed by Chen et al.using triplet of N VI. A relative higher diagnosed electron density from R 2 is due to its weak sensitivity to electron temperature. A better consistency at lower T e indicates that temperature of the laboratory plasma is lower than logT e (K)=6.5. Comparison between the measured and theoretical ratios

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Section: Resultssupporting

confidence: 93%

Electron density diagnostic potential of Ar XIV soft X-ray emission lines

Liang

Zhao

Zeng

et al. 2006

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…The residual gas pressure is lower than 10 −11 mbar. Together with an electron density n e ≤ 10 12 cm −3 (Chen et al 2004), the conditions approximate the dilute plasma conditions of the solar corona.…”

Section: Measurementmentioning

confidence: 81%

Low-density laboratory spectra near the He iiλ304 line

Beiersdörfer

Brickhouse

Golub

2016

A&A

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Aims. To interpret the EUV spectra of the solar corona, one hopes for laboratory data of specific chemical elements obtained under coronal conditions. Methods. EUV spectra of He, C, N, O, F, Ne, S, Ar, Fe, and Ni in a 40 Å wide wavelength interval near λ304 were excited in an electron beam ion trap. Results. We observe some two hundred lines about half of which are not yet identified and included in spectral models. Conclusions. Our data provide a check on the atomic data bases underlying the spectral models that are used to interpret solar corona data. However, a multitude of mostly weak additional lines taken together represent a flux that is comparable to that of various primary lines.

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“…In general, the trapped ions have a wider distribution compared with the electron beam as reported in several previous studies (Gillaspy et al 1995;Chen et al 2004;Silver et al 2000;Liang et al 2009b;Nakamura et al 2011). The effective density n eff e therefore becomes smaller than the geometrical density n g e .…”

Section: Electron Densitiesmentioning

confidence: 61%

“…In most of the previous measurements performed on EBITs, theoretically estimated electron-ion overlap factor have been used to derive electron densities and thus corresponding density sensitive line ratios (Liang et al 2009a,b;Chen et al 2004;Yamamotto et al 2008). This resulted in uncertainties in the measured electron density values.…”

Section: Experiments and Data Analysismentioning

confidence: 99%

Measurements of density dependent intensity ratios of extreme ultraviolet line emission from Fe X, XI, and XII

Shimizu

Ali

Tsuda

et al. 2017

A&A

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We report high-resolution density dependent intensity ratio measurements for middle charge states of iron in the extreme ultraviolet (EUV) spectral wavelength range of 160−200 Å. The measurements were performed at the Tokyo EBIT laboratory by employing a flat-field grazing incidence spectrometer installed on a low energy compact electron beam ion trap. The intensity ratios for several line pairs stemming from Fe X, Fe XI and Fe XII were extracted from spectra collected at the electron beam energies of 340 and 400 eV by varying the beam current between 7.5 and 12 mA at each energy. In addition, the effective electron densities were obtained experimentally by imaging the electron beam profile and ion cloud size with a pinhole camera and visible spectrometer, respectively. In this paper, the experimental results are compared with previous data from the literature and with the present calculations performed using a collisional-radiative model. Our experimental results show a rather good agreement with the calculations and previous reported results.

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Experimental and Theoretical Evaluation of Density‐sensitive Nvi, Arxiv, and FexxiiLine Ratios

Cited by 54 publications

References 29 publications

Electron density diagnostic potential of Ar XIV soft X-ray emission lines

Electron density diagnostic potential of Ar XIV soft X-ray emission lines

Low-density laboratory spectra near the He iiλ304 line

Measurements of density dependent intensity ratios of extreme ultraviolet line emission from Fe X, XI, and XII

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