IRIS Observations of Spicules and Structures Near the Solar Limb
We have analyzed IRIS spectral and slit-jaw observations of a quiet region near the South Pole. In this article we present an overview of the observations, the corrections, and the absolute calibration of the intensity. We focus on the average profiles of strong (Mg ii h and k, C ii and Si iv), as w...
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ftdatacite:10.48550/arxiv.1801.02082 2023-05-15T18:23:19+02:00 IRIS Observations of Spicules and Structures Near the Solar Limb Alissandrakis, C. E. Vial, J. -C. Koukras, A. Buchlin, E. Chane-Yook, M. 2018 https://dx.doi.org/10.48550/arxiv.1801.02082 https://arxiv.org/abs/1801.02082 unknown arXiv https://dx.doi.org/10.1007/s11207-018-1242-4 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences article-journal Article ScholarlyArticle Text 2018 ftdatacite https://doi.org/10.48550/arxiv.1801.02082 https://doi.org/10.1007/s11207-018-1242-4 2022-04-01T09:57:43Z We have analyzed IRIS spectral and slit-jaw observations of a quiet region near the South Pole. In this article we present an overview of the observations, the corrections, and the absolute calibration of the intensity. We focus on the average profiles of strong (Mg ii h and k, C ii and Si iv), as well as of weak spectral lines in the near ultraviolet (NUV) and the far ultraviolet (FUV), including the Mg ii triplet, thus probing the solar atmosphere from the low chromosphere to the transition region. We give the radial variation of bulk spectral parameters as well as line ratios and turbulent velocities. We present measurements of the formation height in lines and in the NUV continuum, from which we find a linear relationship between the position of the limb and the intensity scale height. We also find that low forming lines, such as the Mg ii triplet, show no temporal variations above the limb associated with spicules, suggesting that such lines are formed in a homogeneous atmospheric layer and, possibly, that spicules are formed above the height of 2 arc sec. We discuss the spatio-temporal structure near the limb from images of intensity as a function of position and time. In these images, we identify p-mode oscillations in the cores of lines formed at low heights above the photosphere, slow moving bright features in O i and fast moving bright features in C ii. Finally, we compare the Mg ii k and h line profiles, together with intensity values of the Balmer lines from the literature, with computations from the PROM57Mg non-LTE model developed at the Institut d'Astrophysique Spatiale and estimated values of the physical parameters. We obtain electron temperatures in the range of $\sim8000$ K at small heights to $\sim20000$ K at large heights, electron densities from $1.1 \times 10^{11}$ to $4 \times 10^{10}$ cm$^{-3}$ and a turbulent velocity of $\sim24$km/s. : Accepted for publication in Solar Physics Text South pole DataCite Metadata Store (German National Library of Science and Technology) South Pole |
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Open Polar |
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DataCite Metadata Store (German National Library of Science and Technology) |
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unknown |
topic |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
spellingShingle |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences Alissandrakis, C. E. Vial, J. -C. Koukras, A. Buchlin, E. Chane-Yook, M. IRIS Observations of Spicules and Structures Near the Solar Limb |
topic_facet |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
description |
We have analyzed IRIS spectral and slit-jaw observations of a quiet region near the South Pole. In this article we present an overview of the observations, the corrections, and the absolute calibration of the intensity. We focus on the average profiles of strong (Mg ii h and k, C ii and Si iv), as well as of weak spectral lines in the near ultraviolet (NUV) and the far ultraviolet (FUV), including the Mg ii triplet, thus probing the solar atmosphere from the low chromosphere to the transition region. We give the radial variation of bulk spectral parameters as well as line ratios and turbulent velocities. We present measurements of the formation height in lines and in the NUV continuum, from which we find a linear relationship between the position of the limb and the intensity scale height. We also find that low forming lines, such as the Mg ii triplet, show no temporal variations above the limb associated with spicules, suggesting that such lines are formed in a homogeneous atmospheric layer and, possibly, that spicules are formed above the height of 2 arc sec. We discuss the spatio-temporal structure near the limb from images of intensity as a function of position and time. In these images, we identify p-mode oscillations in the cores of lines formed at low heights above the photosphere, slow moving bright features in O i and fast moving bright features in C ii. Finally, we compare the Mg ii k and h line profiles, together with intensity values of the Balmer lines from the literature, with computations from the PROM57Mg non-LTE model developed at the Institut d'Astrophysique Spatiale and estimated values of the physical parameters. We obtain electron temperatures in the range of $\sim8000$ K at small heights to $\sim20000$ K at large heights, electron densities from $1.1 \times 10^{11}$ to $4 \times 10^{10}$ cm$^{-3}$ and a turbulent velocity of $\sim24$km/s. : Accepted for publication in Solar Physics |
format |
Text |
author |
Alissandrakis, C. E. Vial, J. -C. Koukras, A. Buchlin, E. Chane-Yook, M. |
author_facet |
Alissandrakis, C. E. Vial, J. -C. Koukras, A. Buchlin, E. Chane-Yook, M. |
author_sort |
Alissandrakis, C. E. |
title |
IRIS Observations of Spicules and Structures Near the Solar Limb |
title_short |
IRIS Observations of Spicules and Structures Near the Solar Limb |
title_full |
IRIS Observations of Spicules and Structures Near the Solar Limb |
title_fullStr |
IRIS Observations of Spicules and Structures Near the Solar Limb |
title_full_unstemmed |
IRIS Observations of Spicules and Structures Near the Solar Limb |
title_sort |
iris observations of spicules and structures near the solar limb |
publisher |
arXiv |
publishDate |
2018 |
url |
https://dx.doi.org/10.48550/arxiv.1801.02082 https://arxiv.org/abs/1801.02082 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
https://dx.doi.org/10.1007/s11207-018-1242-4 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1801.02082 https://doi.org/10.1007/s11207-018-1242-4 |
_version_ |
1766202875913961472 |