Coronal Density and Temperature Profiles Calculated by Forward Modeling EUV Emission Observed by SDO/AIA

Pascoe, D. J.; Smyrli, Aimilia; Doorsselaere, Tom Van

doi:10.3847/1538-4357/ab3e39

Cited by 13 publications

(9 citation statements)

References 69 publications

(69 reference statements)

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“…They suggested that the density derived from the cooler lines (Fe VIII) probes the cool coronal hole plasma and the hotter lines show a contribution from quiet-Sun plasma. This also agrees with the results by Pascoe, Smyrli, and Van Doorsselaere (2019) that estimated coronal hole electron densities are around ≈ 10 8 cm −3 . Figure 8 shows that the density decreases as a function of the distance from the coronal hole boundary up to d ≈ 20 .…”

Section: Discussionsupporting

confidence: 93%

Statistical Approach on Differential Emission Measure of Coronal Holes using the CATCH Catalog

et al. 2021

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Coronal holes are large-scale structures in the solar atmosphere that feature a reduced temperature and density in comparison to the surrounding quiet Sun and are usually associated with open magnetic fields. We perform a differential emission measure analysis on the 707 non-polar coronal holes in the Collection of Analysis Tools for Coronal Holes (CATCH) catalog to derive and statistically analyze their plasma properties (i.e. temperature, electron density, and emission measure). We use intensity filtergrams of the six coronal EUV filters from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, which cover a temperature range from $\approx10^{5.5}$ ≈ 10 5.5 to $10^{7.5}~\mbox{K}$ 10 7.5 K . Correcting the data for stray and scattered light, we find that all coronal holes have very similar plasma properties with an average temperature of $0.94 \pm0.18~\mbox{MK}$ 0.94 ± 0.18 MK , a mean electron density of $(2.4 \pm0.7) \times10^{8}~\mbox{cm}^{-3}$ ( 2.4 ± 0.7 ) × 10 8 cm − 3 , and a mean emission measure of $(2.8 \pm1.6) \times10^{26}~\mbox{cm}^{-5}$ ( 2.8 ± 1.6 ) × 10 26 cm − 5 . The temperature distribution within the coronal holes was found to be largely uniform, whereas the electron density shows a 30 to 40% linear decrease from the boundary towards the inside of the coronal hole. At distances greater than 20″ ($\approx15~\mbox{Mm}$ ≈ 15 Mm ) from the nearest coronal hole boundary, the density also becomes statistically uniform. The coronal hole temperature may show a weak solar-cycle dependency, but no statistically significant correlation of plasma properties with solar-cycle variations could be determined throughout the observed period between 2010 and 2019.

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Section: Discussionsupporting

confidence: 93%

Statistical Approach on Differential Emission Measure of Coronal Holes using the CATCH Catalog

et al. 2021

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“…The extent to which this is due to observational issues, rather than genuine evolution of the loops, remains to be determined. That study was also based on DEM analysis which is known to produce overly broad spectra (e.g., Van Doorsselaere et al, 2018;Pascoe et al, 2019b) which may conceal the signatures of KHI.…”

Section: Discussionmentioning

confidence: 99%

Oscillation and Evolution of Coronal Loops in a Dynamical Solar Corona

Pascoe

Goddard

Doorsselaere

2020

Front. Astron. Space Sci.

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“…This broadness can be overestimated by DEM inversions (e.g. Van Doorsselaere et al 2018;Pascoe et al 2019b). Changes in loop intensity can also be associated with radiative cooling, with typical cooling times being tens of minutes (e.g.…”

Section: Analysis Of Kink Oscillationsmentioning

confidence: 99%

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

Pascoe

Smyrli

Doorsselaere

2020

ApJ

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We present a new method to track the position and evolution of coronal loops designed for observations such as active regions in which multiple loops appear in close proximity or overlap with each other along the observational line of sight. The method is based on modeling a time-distance map containing one or more loops and fitting the modeled map to observational data, as opposed to the commonly used technique of analysing each frame independently. This allows us to control the variability of the model, informed by our physical interpretation, and use the trends present to help constrain the model parameters. We apply our method to an observation of a bundle of coronal loops previously investigated using a spatio-temporal autocorrelation method and compare our results. A benefit of our method is that it provides the time series for the position of the loops which may be used for further analysis using established seismological techniques. We demonstrate this by modeling the oscillation of several loops in response to flaring energy releases that occur during the observation, and find evidence of loop evolution consistent with the Kelvin-Helmholtz instability.

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Coronal Density and Temperature Profiles Calculated by Forward Modeling EUV Emission Observed by SDO/AIA

Cited by 13 publications

References 69 publications

Statistical Approach on Differential Emission Measure of Coronal Holes using the CATCH Catalog

Statistical Approach on Differential Emission Measure of Coronal Holes using the CATCH Catalog

Oscillation and Evolution of Coronal Loops in a Dynamical Solar Corona

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

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