Optics and mechanisms for the Extreme-Ultraviolet Imaging Spectrometer on the Solar-B satellite

Korendyke, C. M.; Brown, C. M.; Thomas, R. J.; Keyser, Christian; Davila, J. M.; Hagood, R.; Hara, Hirohisa; Heidemann, Klaus; James, Ady; Lang, J.; Mariska, J. T.; Moser, John W.; Moye, Robert W.; Myers, S. H.; Probyn, B. J.; Seely, John F.; Shea, J.; Shepler, Ed; Tandy, J. A.

doi:10.1364/ao.45.008674

Cited by 75 publications

(52 citation statements)

References 14 publications

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“…Thus, in the absence of other sources of line broadening and assuming a total Gaussian line shape, the total observed Fe XVI line FWHM should be approximately W = W 2 th + W 2 inst = 0.078 Å . Before its launch, the instrumental profile of EIS was laboratory tested (Korendyke et al 2006) using a limited set of line observations. Although the line profiles were not analysed rigorously, it was concluded that the instrumental profile was adequately fitted with a Gaussian profile, and this is the assumption made in this paper.…”

Section: Hinode Eis Observations Of Fe XVImentioning

confidence: 99%

First evidence of non-Gaussian solar flare EUV spectral line profiles and accelerated non-thermal ion motion

Jeffrey

Fletcher

Labrosse

2016

A&A

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Context. The properties of solar flare plasma can be determined from the observation of optically thin lines. The emitting ion distribution determines the shape of the spectral line profile, with an isothermal Maxwellian ion distribution producing a Gaussian profile. Non-Gaussian line profiles may indicate more complex ion distributions. Aims. We investigate the possibility of determining flare-accelerated non-thermal ion and/or plasma velocity distributions. Methods. We study EUV spectral lines produced during a flare SOL2013-05-15T01:45 using the Hinode EUV Imaging Spectrometer (EIS). The flare is located close to the eastern solar limb with an extended loop structure, allowing the different flare features: ribbons, hard X-ray (HXR) footpoints and the loop-top source to be clearly observed in UV, EUV and X-rays. EUV line spectroscopy is performed in seven different regions covering the flare. We study the line profiles of the isolated and unblended Fe XVI lines (λ262.9760 Å ) mainly formed at temperatures of ∼2 to 4 MK. Suitable Fe XVI line profiles at one time close to the peak soft X-ray emission and free of directed mass motions are examined using: 1. a higher moments analysis, 2. Gaussian fitting, and 3. by fitting a kappa distribution line profile convolved with a Gaussian to account for the EIS instrumental profile. Results. Fe XVI line profiles in the flaring loop-top, HXR footpoint and ribbon regions can be confidently fitted with a kappa line profile with an extra variable κ, giving low, non-thermal κ values between 2 and 3.3. An independent higher moments analysis also finds that many of the spectral line kurtosis values are higher than the Gaussian value of 3, even with the presence of a broad Gaussian instrumental profile. Conclusions. A flare-accelerated non-thermal ion population could account for both the observed non-Gaussian line profiles, and for the Fe XVI "excess" broadening found from Gaussian fitting, if the emitting ions are interacting with a thermalised ∼4 MK electron population, and the instrumental profile is well-approximated by a Gaussian profile.

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Section: Hinode Eis Observations Of Fe XVImentioning

confidence: 99%

First evidence of non-Gaussian solar flare EUV spectral line profiles and accelerated non-thermal ion motion

Jeffrey

Fletcher

Labrosse

2016

A&A

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“…The instrument has 1Љ spatial pixels and 22.3 m spec-Å A tral pixels. Further details are given in Culhane et al (2007) and Korendyke et al (2006).…”

Section: Observationsmentioning

confidence: 99%

Observations of Active Region Loops with the EUV Imaging Spectrometer on Hinode

Warren

Ugarte-Urra

Doschek

et al. 2008

ApJ

105

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Previous solar observations have shown that coronal loops near 1 MK are difficult to reconcile with simple heating models. These loops have lifetimes that are long relative to a radiative cooling time, suggesting quasisteady heating. The electron densities in these loops, however, are too high to be consistent with thermodynamic equilibrium. Models proposed to explain these properties generally rely on the existence of smaller scale filaments within the loop that are in various stages of heating and cooling. Such a framework implies that there should be a distribution of temperatures within a coronal loop. In this paper we analyze new observations from the EUV Imaging Spectrometer (EIS) on Hinode. EIS is capable of observing active regions over a wide range of temperatures (Fe viii-Fe xvii) at relatively high spatial resolution (1Љ). We find that most isolated coronal loops that are bright in Fe xii generally have very narrow temperature distributions ( K), but are not isothermal.We also derive volumetric filling factors in these loops of approximately 10%. Both results lend support to the filament models.

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“…However, as the λ209.9 line is located at the long wavelength edge of the EIS wavelength band, the uncertainties in sensitivity of the EIS instrument must be considered. In our analysis, the calibration performed at Naval Research Laboratory (NRL) before the launch is adopted to obtain the spectral sensitivity of the EIS instrument (Korendyke et al 2006).…”

Section: Active Region Data Setmentioning

confidence: 99%

Fe XIII DENSITY DIAGNOSTICS IN THE EIS OBSERVING WAVELENGTHS

Watanabe

Hara

Yamamoto

et al. 2009

ApJ

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The diagnostic capability of Fe xiii line features seen in the 170-210 Å waveband of the EUV Imaging Spectrometer (EIS) on Hinode is investigated, with emphasis on density diagnostics applied to solar active regions. Four diagnostic line pairs are found to yield consistent densities ranging from 10 8.5 to 10 9.5 cm −3 across an active region using a new theoretical model of the ion. In separate EIS observations of a small flare, the widely used line pair, Fe xiii λ203.8/λ202.0, is found to reach the high density limit predicted by a new theoretical model of the iron ion.

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Optics and mechanisms for the Extreme-Ultraviolet Imaging Spectrometer on the Solar-B satellite

Cited by 75 publications

References 14 publications

First evidence of non-Gaussian solar flare EUV spectral line profiles and accelerated non-thermal ion motion

First evidence of non-Gaussian solar flare EUV spectral line profiles and accelerated non-thermal ion motion

Observations of Active Region Loops with the EUV Imaging Spectrometer on Hinode

Fe XIII DENSITY DIAGNOSTICS IN THE EIS OBSERVING WAVELENGTHS

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