Iron emission lines in solar and laboratory plasmas

Lepson, J. K.; Beiersdörfer, P.; Hurwitz, M.; Sirk, Martin M.; Katō, Takako; Yamamoto, Norimasa

doi:10.1088/1742-6596/130/1/012014

Cited by 10 publications

(3 citation statements)

References 19 publications

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“…Emission from Fe IX have been observed in laboratory plasmas, for example, those produced in magnetic fusion devices [1][2][3][4], and in space plasmas, for example, in stellar coronae, including the Sun [5][6][7][8][9][10]. The strongest Fe IX line in the extreme ultraviolet wavelength band is situated at 171 Å and is well known.…”

Section: Introductionmentioning

confidence: 99%

High-Resolution Laboratory Measurements and Identification of Fe IX Lines near 171 Å

Beiersdörfer

Lepson

Brown

et al. 2022

Atoms

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A multitude of weaker Fe IX lines have been predicted in the vicinity of the strong 171 Å line that dominates the spectra of many astrophysical and laboratory sources. Some of these weaker lines have only recently been identified in the laboratory, albeit some only tentatively. Here, we present measurements on the Livermore EBIT-I electron beam ion trap that span the region from 170.0 to 173.6 Å, which surrounds the 171 Å line. The measurements stepped through electron beam energy to determine the charge state of iron associated with each observed feature. Moreover, we have minimized the presence of oxygen in the trap, because oxygen lines obscured possible Fe IX lines in past measurements and prevented their identification. Our measurement confirms formerly tentative identifications and adds several new assignments.

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Section: Introductionmentioning

confidence: 99%

High-Resolution Laboratory Measurements and Identification of Fe IX Lines near 171 Å

Beiersdörfer

Lepson

Brown

et al. 2022

Atoms

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“…So far, the EUV emission spectra of highly charged iron, notably Fe VIII through Fe XV have been observed from astrophysical observations and identified with the help of experimental data (Thomas & Neupert 1994;Young et al 2007;Yamamotto et al 2008;Lepson et al 2008;Del Zanna 2012;Brickhouse et al 1995;Schmitt et al 1996;Feldman et al 2008;Beiersdorfer et al 2012Beiersdorfer et al , 2014a. However, density dependent line ratios data for these ions and in particular Fe X to XII, is still not very well known.…”

Section: Introductionmentioning

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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“…This spectrum is utilized to cross-check the quality of the solar observations and the calibration of the CHIPS throughput. An uncalibrated, mean CHIPS spectrum was first presented by Hurwitz et al (2006), and compared to laboratory plasmas by Lepson et al (2008).…”

Section: Introductionmentioning

confidence: 99%

EUV Spectra of the Full Solar Disk: Analysis and Results of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)

2010

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We analyze EUV spectra of the full solar disk from the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) spanning a period of two years. The observations were obtained via a fortuitous off-axis light path in the 140 -275 Å passband. The general appearance of the spectra remained relatively stable over the two-year time period, but did show significant variations of up to 25% between two sets of Fe lines that show peak emission at 1 MK and 2 MK. The variations occur at a measured period of 27.2 days and are caused by regions of hotter and cooler plasma rotating into, and out of, the field of view. The CHI-ANTI spectral code is employed to determine plasma temperatures, densities, and emission measures. A set of five isothermal plasmas fit the full-disk spectra well. A 1 -2 MK plasma of Fe contributes 85% of the total emission in the CHIPS passband. The standard Differential Emission Measures (DEMs) supplied with the CHIANTI package do not fit the CHIPS spectra well as they over-predict emission at temperatures below log 10 T = 6.0 and above log 10 T = 6.3. The results are important for cross-calibrating TIMED, SORCE, SOHO/EIT, and CDS/GIS, as well as the recently launched Solar Dynamics Observatory.

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Iron emission lines in solar and laboratory plasmas

Cited by 10 publications

References 19 publications

High-Resolution Laboratory Measurements and Identification of Fe IX Lines near 171 Å

High-Resolution Laboratory Measurements and Identification of Fe IX Lines near 171 Å

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

EUV Spectra of the Full Solar Disk: Analysis and Results of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)

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