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Observational signatures of the third harmonic in a decaying kink oscillation of a coronal loop
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Duckenfield, Timothy, Goddard, Christopher R., Pascoe, D. J. (David J.) and Nakariakov, V. M. (Valery M.) (2019) Observational signatures of the third harmonic in a decaying kink oscillation of a coronal loop. Astronomy & Astrophysics, 632 . A64. doi:10.1051/0004-6361/201936822 ISSN 0004-6361.
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Official URL: http://dx.doi.org/10.1051/0004-6361/201936822
Abstract
Aims. An observation of a coronal loop standing kink mode is analysed to search for higher harmonics, aiming to reveal the relation
between di erent harmonics’ quality factors.
Methods. Observations of a coronal loop were taken by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory
(SDO). The loop’s axis was tracked at many spatial positions along the loop to generate time series data.
Results. The distribution of spectral power of the oscillatory transverse displacements throughout the loop reveals the presence of two
harmonics, a fundamental at a period of 8 minutes and its third harmonic at 2.6 minutes. The node of the third harmonic is seen
at approximately a third of the way along the length of the loop, and cross correlations between the oscillatory motion on opposing
sides of the node show a change in phase behaviour. The ratio of periods P1=3P3 was found to be 0:87, indicating a non-uniform
distribution of kink speed through the loop. The quality factor for the fundamental mode of oscillation was measured to be 3:4. The
quality factor of the third harmonic was measured for each spatial location and, where data was reliable, yielded a value of 3:6.
For all locations, the quality factors for the two harmonics were found to agree within error as expected from 1d resonant absorption
theory. This is the first time a measurement of the signal quality for a higher harmonic of a kink oscillation has been reported with
spatially resolved data.
Item Type: | Journal Article | ||||||||||||||||||
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Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | ||||||||||||||||||
Library of Congress Subject Headings (LCSH): | Magnetohydrodynamics -- Research, Sun -- Corona , Sun -- Corona -- Magnetic fields, Solar oscillations , Solar radiation | ||||||||||||||||||
Journal or Publication Title: | Astronomy & Astrophysics | ||||||||||||||||||
Publisher: | EDP Sciences | ||||||||||||||||||
ISSN: | 0004-6361 | ||||||||||||||||||
Official Date: | December 2019 | ||||||||||||||||||
Dates: |
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Volume: | 632 | ||||||||||||||||||
Article Number: | A64 | ||||||||||||||||||
DOI: | 10.1051/0004-6361/201936822 | ||||||||||||||||||
Status: | Peer Reviewed | ||||||||||||||||||
Publication Status: | Published | ||||||||||||||||||
Reuse Statement (publisher, data, author rights): | “Reproduced with permission from Astronomy & Astrophysics, © ESO”. | ||||||||||||||||||
Access rights to Published version: | Restricted or Subscription Access | ||||||||||||||||||
Copyright Holders: | © ESO | ||||||||||||||||||
Date of first compliant deposit: | 31 October 2019 | ||||||||||||||||||
Date of first compliant Open Access: | 31 October 2019 | ||||||||||||||||||
RIOXX Funder/Project Grant: |
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