A Theoretical Investigation of the Magnetic-field-induced Transition in Fe X, of Importance for Measuring Magnetic Field Strengths in the Solar Corona

Li, W.; Li, M.; Wang, K.; Brage, Tomas; Hutton, R.; Landi, E.

doi:10.3847/1538-4357/abfa97

Cited by 23 publications

(25 citation statements)

References 44 publications

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“…Judge et al (2016) and Landi et al (2020b) analyzed the astronomical observation of spectral line 1603 Å decaying from an upper level 3p 4 3d 2 G 7/2 to 4 D 5/2, 7/2 , and proposed ΔE of 3.6 ± 2.9 cm −1 and 2.29 ± 0.50 cm −1 , respectively. Recently, Li et al (2021) employed four calculation schemes and considered that the computation of ΔE exceeds the precision limits of current theoretical calculations, and therefore recommended the value of 2.29 ± 0.50 cm −1 . So there is at least a 20% uncertainty for the ΔE, and it is still important (though tough) work to measure the value of ΔE in the laboratory.…”

Section: Energy Separation δEmentioning

confidence: 99%

“…The electron beam energy and current were set to 210 eV and 6.8 mA. uncertainty of A MIT was estimated to be 5% (Li et al 2021).…”

Section: Energy Separation δEmentioning

confidence: 99%

“…However, the effect of the MIT in Fe X at different magnetic fields has not yet been verified experimentally. There are also some nonnegligible uncertainties regarding the key parameter ΔE and the simulation method itself (Landi et al 2020a;Li et al 2021). The ΔE value varies by one order of magnitude in different calculations and is acquired from different measurements with at least 20% uncertainty, e.g., 3.6 ± 2.9 cm −1 (Judge et al 2016) and 2.29 ± 0.50 cm −1 (Landi et al 2020b).…”

Section: Introductionmentioning

confidence: 99%

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First Laboratory Measurement of Magnetic-field-induced Transition Effect in Fe x at Different Magnetic Fields

Yan

et al. 2022

ApJ

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The magnetic field is extremely important for understanding the properties of the solar corona. However, there are still difficulties in the direct measurement of the coronal magnetic field. The magnetic-field-induced transition (MIT) in Fe x, appearing in coronal spectra, was discovered to have prospective applications in coronal magnetic field measurements. In this work, we obtained the extreme ultraviolet spectra of Fe x in the wavelength range of 174–267 Å in the Shanghai High-temperature Superconducting Electron Beam Ion Trap, and examined the effect of MIT in Fe x by measuring the line ratios between 257.262 Å and the reference line of 226.31 Å (257/226) at different magnetic field strengths for the first time. The electron density that may affect the 257/226 value was also obtained experimentally and verified by comparing the density-sensitive line ratio (175.266 Å/174.534 Å) measurements with the theoretical predictions, and there was good agreement between them. The energy separation between the two levels of 3s23p43d 4 D 5/2 and 3s23p43d 4 D 7/2, one of the most critical parameters for determining the MIT rate, was obtained by analyzing the simulated line ratios of 257/226 with the experimental values at the given electron densities and magnetic fields. Possible reasons that may have led to the difference between the obtained energy splitting and the recommended value in previous works are discussed. Magnetic field response curves for the 257/226 value were calculated and compared to the experimental results, which is necessary for future MIT diagnostics.

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Section: Energy Separation δEmentioning

confidence: 99%

“…The electron beam energy and current were set to 210 eV and 6.8 mA. uncertainty of A MIT was estimated to be 5% (Li et al 2021).…”

Section: Energy Separation δEmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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First Laboratory Measurement of Magnetic-field-induced Transition Effect in Fe x at Different Magnetic Fields

Yan

et al. 2022

ApJ

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“…To synthesize the coronal emissions, we followed Chen et al ( 2021) and calculated the contribution functions G(T, n e , B) of the Fe x 174, 175, 177, 184 and 257 Å lines as a function of electron temperature, density, and magnetic field strength (Li et al 2021).…”

Section: Models and Emission Line Synthesismentioning

confidence: 99%

Measurements of the magnetic field strengths at the bases of stellar coronae using the magnetic-field-induced transition theory

Chen,

Liu,

Tian

et al. 2021

Preprint

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Measurements of the magnetic field in the stellar coronae are extremely difficult. Recently, it was proposed that the magnetic-field-induced transition (MIT) of the Fe x 257 Å line can be used to measure the coronal magnetic field of the Sun. We performed forward modeling with a series of global stellar magnetohydrodynamics models to investigate the possibility of extending this method to other late-type stars. We first synthesized the emissions of several Fe x lines for each stellar model, then calculated the magnetic field strengths using the intensity ratios of Fe x 257 Å to several other Fe x lines based on the MIT theory. Finally, we compared the derived field strengths with those in the models, and concluded that this method can be used to measure at least the magnetic field strengths at the coronal bases of stars with a mean surface magnetic flux density about one order of magnitude higher than that of the Sun. Our investigation suggests the need of an extreme ultraviolet spectrometer to perform routine measurements of the stellar coronal magnetic field.

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“…We used CHIANTI database (version 10.0; Dere et al 1997;Del Zanna et al 2021) to calculate the line emissivities. The original source for these data are Del Zanna et al (2012) for level energies and collision data, Wang et al (2020) for radiative transition data, and Li et al (2021) for A MIT values.…”

Section: Fe X Lines Used For Magnetic Field Diagnosticsmentioning

confidence: 99%

Forward Modeling of Solar Coronal Magnetic Field Measurements Based on a Magnetic-field-induced Transition in Fe X

Chen,

Li,

Tian

et al. 2021

Preprint

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It was recently proposed that the intensity ratios of several extreme ultraviolet spectral lines from the Fe x ion can be used to measure the solar coronal magnetic field based on the magnetic-field-induced transition (MIT) theory. To verify the suitability of this method, we performed forward modeling with a three-dimensional radiation magnetohydrodynamic model of a solar active region. Intensities of several spectral lines from Fe x were synthesized from the model. Based on the MIT theory, intensity ratios of the MIT line Fe x 257 Å to several other Fe x lines were used to derive the magnetic field strengths, which were then compared with the field strengths in the model. We also developed a new method to simultaneously estimate the coronal density and temperature from the Fe x 174/175 and 184/345 Å line ratios. Using these estimates, we demonstrated that the MIT technique can provide reasonably accurate measurements of the coronal magnetic field in both on-disk and off-limb solar observations. Our investigation suggests that a spectrometer that can simultaneously observe the Fe x 174, 175, 184, 257, and 345 Å lines and allow an accurate radiometric calibration for these lines is highly desired to achieve reliable measurements of the coronal magnetic field. We have also evaluated the impact of the uncertainty in the Fe x 3p 4 3d 4 D 5/2 and 4 D 7/2 energy difference on the magnetic field measurements.

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A Theoretical Investigation of the Magnetic-field-induced Transition in Fe X, of Importance for Measuring Magnetic Field Strengths in the Solar Corona

Cited by 23 publications

References 44 publications

First Laboratory Measurement of Magnetic-field-induced Transition Effect in Fe x at Different Magnetic Fields

First Laboratory Measurement of Magnetic-field-induced Transition Effect in Fe x at Different Magnetic Fields

Measurements of the magnetic field strengths at the bases of stellar coronae using the magnetic-field-induced transition theory

Forward Modeling of Solar Coronal Magnetic Field Measurements Based on a Magnetic-field-induced Transition in Fe X

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