Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops
Kink oscillations of coronal loops have been widely studied, both observationally and theoretically, over the past few decades. It has been shown that the majority of observed driven coronal loop oscillations appear to damp with either exponential or Gaussian profiles and a range of mechanisms have...
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Frontiers Media S.A.
2021-01-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2020.579585/full |
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| author | Daria Shukhobodskaia Alexander A. Shukhobodskiy Chris J. Nelson Michael S. Ruderman Michael S. Ruderman Robert Erdélyi Robert Erdélyi |
| author_facet | Daria Shukhobodskaia Alexander A. Shukhobodskiy Chris J. Nelson Michael S. Ruderman Michael S. Ruderman Robert Erdélyi Robert Erdélyi |
| author_sort | Daria Shukhobodskaia |
| collection | DOAJ |
| description | Kink oscillations of coronal loops have been widely studied, both observationally and theoretically, over the past few decades. It has been shown that the majority of observed driven coronal loop oscillations appear to damp with either exponential or Gaussian profiles and a range of mechanisms have been proposed to account for this. However, some driven oscillations seem to evolve in manners which cannot be modeled with purely Gaussian or exponential profiles, with amplification of oscillations even being observed on occasions. Recent research has shown that incorporating the combined effects of coronal loop expansion, resonant absorption, and cooling can cause significant deviations from Gaussian and exponential profiles in damping profiles, potentially explaining increases in oscillation amplitude through time in some cases. In this article, we analyze 10 driven kink oscillations in coronal loops to further investigate the ability of expansion and cooling to explain complex damping profiles. Our results do not rely on fitting a periodicity to the oscillations meaning complexities in both temporal (period changes) and spatial (amplitude changes) can be accounted for in an elegant and simple way. Furthermore, this approach could also allow us to infer some important diagnostic information (such as, for example, the density ratio at the loop foot-points) from the oscillation profile alone, without detailed measurements of the loop and without complex numerical methods. Our results imply the existence of correlations between the density ratio at the loop foot-points and the amplitudes and periods of the oscillations. Finally, we compare our results to previous models, namely purely Gaussian and purely exponential damping profiles, through the calculation of χ2 values, finding the inclusion of cooling can produce better fits in some cases. The current study indicates that thermal evolution should be included in kink-mode oscillation models in the future to help us to better understand oscillations that are not purely Gaussian or exponential. |
| first_indexed | 2024-12-17T04:59:58Z |
| format | Article |
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| issn | 2296-987X |
| language | English |
| last_indexed | 2024-12-17T04:59:58Z |
| publishDate | 2021-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-820561c1786944c3849aee07674ca5222022-12-21T22:02:35ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2021-01-01710.3389/fspas.2020.579585579585Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal LoopsDaria Shukhobodskaia0Alexander A. Shukhobodskiy1Chris J. Nelson2Michael S. Ruderman3Michael S. Ruderman4Robert Erdélyi5Robert Erdélyi6Solar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield, United KingdomSchool of Build Environment, Engineering and Computing, Leeds Beckett University, Leeds, United KingdomAstrophysics Research Centre (ARC), School of Mathematics and Physics, Queen’s University, Belfast, United KingdomSolar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield, United KingdomLaboratory of Interplanetary Medium, Space Research Institute (IKI) Russian Academy of Sciences, Moscow, RussiaSolar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield, United KingdomDepartment of Astronomy, Eötvös Loránd University, Budapest, HungaryKink oscillations of coronal loops have been widely studied, both observationally and theoretically, over the past few decades. It has been shown that the majority of observed driven coronal loop oscillations appear to damp with either exponential or Gaussian profiles and a range of mechanisms have been proposed to account for this. However, some driven oscillations seem to evolve in manners which cannot be modeled with purely Gaussian or exponential profiles, with amplification of oscillations even being observed on occasions. Recent research has shown that incorporating the combined effects of coronal loop expansion, resonant absorption, and cooling can cause significant deviations from Gaussian and exponential profiles in damping profiles, potentially explaining increases in oscillation amplitude through time in some cases. In this article, we analyze 10 driven kink oscillations in coronal loops to further investigate the ability of expansion and cooling to explain complex damping profiles. Our results do not rely on fitting a periodicity to the oscillations meaning complexities in both temporal (period changes) and spatial (amplitude changes) can be accounted for in an elegant and simple way. Furthermore, this approach could also allow us to infer some important diagnostic information (such as, for example, the density ratio at the loop foot-points) from the oscillation profile alone, without detailed measurements of the loop and without complex numerical methods. Our results imply the existence of correlations between the density ratio at the loop foot-points and the amplitudes and periods of the oscillations. Finally, we compare our results to previous models, namely purely Gaussian and purely exponential damping profiles, through the calculation of χ2 values, finding the inclusion of cooling can produce better fits in some cases. The current study indicates that thermal evolution should be included in kink-mode oscillation models in the future to help us to better understand oscillations that are not purely Gaussian or exponential.https://www.frontiersin.org/articles/10.3389/fspas.2020.579585/fullsolar coronacoronal loop oscillationsmagnetohydrodynamicskink oscillationswaves |
| spellingShingle | Daria Shukhobodskaia Alexander A. Shukhobodskiy Chris J. Nelson Michael S. Ruderman Michael S. Ruderman Robert Erdélyi Robert Erdélyi Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops Frontiers in Astronomy and Space Sciences solar corona coronal loop oscillations magnetohydrodynamics kink oscillations waves |
| title | Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops |
| title_full | Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops |
| title_fullStr | Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops |
| title_full_unstemmed | Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops |
| title_short | Significance of Cooling Effect on Comprehension of Kink Oscillations of Coronal Loops |
| title_sort | significance of cooling effect on comprehension of kink oscillations of coronal loops |
| topic | solar corona coronal loop oscillations magnetohydrodynamics kink oscillations waves |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2020.579585/full |
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