Forbidden lines of highly ionized iron in solar flare spectra

Doschek, G. A.; Dere, K. P.; Sandlin, G. D.; Vanhoosier, M. E.; Brueckner, G. E.; Purcell, J. D.; Tousey, R.; Feldman, U.

doi:10.1086/181749

Cited by 64 publications

(48 citation statements)

References 8 publications

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“…Some of the recorded lines were previously observed in solar spectra (e.g., Doschek et al 1975 ;Sandlin, Brueckner & Tousey 1977 ;Feldman & Doschek 1991 ;Feldman et al 1998a ;Kucera et al 2000). A number of additional lines were previously observed in spectra emitted by tokamak plasmas and by beam-foil sources (e.g., Denne & Hinnov 1984 ;Hinnov & Suckewer 1980 ;Hinnov et al 1982 ;Peacock, Stamp, & Silver 1984).…”

Section: High-temperature Spectral Lines In the Sumer Range And Infermentioning

confidence: 70%

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics

Feldman

Curdt

Landi

et al. 2000

ApJ

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On 1999 May 9 the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) recorded spectra from a high-temperature region located in the solar corona above the west limb. These spectra contain lines from rather less-abundant elements in solar plasmas. In this paper we present identiÐcations of the high-temperature K) Ne, (T e º 3 ] 106 Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni lines that were detected in the 500È1600 spectral range A of SUMER. In addition, accurate wavelength measurements have been obtained with uncertainties varying between 0.015 and 0.040(1 p). Making use of the newly measured wavelengths, we derive A energy levels in the ground conÐguration of a number of highly charged ions. We present intensity ratio calculations of lines in the SUMER range that could be used to measure electron densities in hightemperature solar plasmas. We also provide emissivities for Ca XIIIÈCa XV and Fe XVIIIÈFe XXIII lines that could be used to determine emission measures and electron temperatures of high-temperature plasmas. We discuss a method for measuring elemental abundance variations in high-temperature solar plasmas using lines presented in the paper. A list of spectral lines spanning the 300È30000 wavelength A range and their branching ratios that are suitable for efficiency calibration of space-borne spectrographs is provided.

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Section: High-temperature Spectral Lines In the Sumer Range And Infermentioning

confidence: 70%

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics

Feldman

Curdt

Landi

et al. 2000

ApJ

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“…Temperatures above 10 MK are quite common in strong flares and lead to spectra with lines of highly ionized species extending into the X-ray range. Flare spectral observations from Skylab instruments S082A and S082B and from SUMER can be found, for instance, in Doschek et al (1975b), Dere (1978), Cohen et al (1978), and Feldman et al (2000b). A class M2 flare was observed by the S082A spectrograph in the He II lines at 25.6 nm and 30.4 nm, and Fe XV at 28.4 nm (Tousey et al 1977).…”

Section: Flaresmentioning

confidence: 98%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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In Part I of this review, the concepts of solar vacuum-ultraviolet (VUV) observations were outlined together with a discussion of the space instrumentation used for the investigations. A section on spectroradiometry provided some quantitative results on the solar VUV radiation without considering any details of the solar phenomena leading to the radiation. Here, in Part II, we present solar VUV observations over the last decades and their interpretations in terms of the plasma processes and the parameters of the solar atmosphere, with emphasis on the spatial and thermal structures of the chromosphere, transition region and corona of the quiet Sun. In addition, observations of active regions, solar flares and prominences are included as well as of small-scale events. Special sections are devoted to the elemental composition of the solar atmosphere and theoretical considerations on the heating of the corona and the generation of the solar wind.

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“…Analysis from these observations provides spectral lines of F-like Fe ion, along with the other multiple charged ions of the lighter elements (Watanabe 2009). A spectral line with wavelength 974 Å of Fe XVIII has also been observed prominently in flaring and solar plasma (Doschek et al 1975) and in the spectrum of the star Capella (Young et al 2001).…”

Section: Introductionmentioning

confidence: 94%

Spectral properties of a few F-like ions

Nandy

Sahoo

2014

A&A

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Aims. We intend to provide accurate data for the oscillator strengths, transition probabilities, lifetimes, and hyperfine shifts of the atomic energy levels in the fluorine (F)-like Ti, V, Cr, Mn, Co, Ni, Cu, Zn, and Mo ions for the diagnostic of the astrophysical plasma. Furthermore, we propose these ions for probing possible variation in the fine structure constant (α e ) by observing their transition lines from the distant astronomical objects. Methods. We have employed an all-order perturbative method in the relativistic coupled-cluster framework using the Dirac-Coulomb Hamiltonian for calculating the atomic wave functions in the considered F-like ions. We adopted the Fock-space formalism to account for the correlation effects among the occupied electrons by allowing all possible singly and doubly excited configurations in two steps: first considering the correlations between the electrons in a closed-shell configuration, and second constructing the openshell configurations of the first three low-lying states in the considered atomic systems by removing the respective electron from the core orbitals. This procedure enormously simplifies the computational complexity and overcomes the need to select important configuration state functions in determining the atomic state functions in contrast to a truncated configuration interaction method. Moreover, corrections from the frequency-independent Breit interaction and the lowest order quantum electrodynamic effects are incorporated self-consistently. Results. We present the calculated ionization potential energies of the electrons that are detached to form the above considered F-like ions. The correctness of our estimated results are ensured by comparing them with the available experimental values and other calculations. From these calculations, we evaluate the relativistic sensitivity coefficients that we propose here to be used for probing possible temporal variation of the fine structure constant (α e ) through the precise astrophysical observation of the spectral lines of the transitions involving the above low-lying states. The accuracies of these sensitivity coefficients are appraised from the comparison of our calculated energies with the experimental values. We also present the line strengths by calculating the reduced matrix elements of the allowed transitions and of the M1 and E2 forbidden transitions. By combining our calculated line strengths with the observed wavelengths, we determine the oscillator strengths, transition probabilities, and lifetimes of the first two excited states of the above ions and compare them with the other theoretical calculations. The hyperfine splittings of the states are also presented by calculating their magnetic dipole and electric quadrupole hyperfine structure constants.

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Forbidden lines of highly ionized iron in solar flare spectra

Cited by 64 publications

References 8 publications

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Spectral properties of a few F-like ions

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Forbidden lines of highly ionized iron in solar flare spectra

Cited by 64 publications

References 8 publications

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (Te≥ 3 x 106K) and Their Potential Use in Plasma Diagnostics

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (Te≥ 3 x 106K) and Their Potential Use in Plasma Diagnostics

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Spectral properties of a few F-like ions

Contact Info

Product

Resources

About

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics

Identification of Spectral Lines in the 500–1600 A Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (T_e≥ 3 x 10⁶K) and Their Potential Use in Plasma Diagnostics