Kink Oscillations Of Coronal Loops Research Articles

Transverse Oscillations and Kelvin–Helmholtz Instability in Curved Arcade Loops with Siphon Flows

The effect of plasma flow in curved arcade loops on transverse waves and oscillations is examined analytically. The model under study is a semicircular magnetic slab with finite transverse extensions and a mass flow inside, in the zero-β plasma approximation. It is found that in the quasi-perpendicular propagation limit, the model supports two fast surface modes: one with higher (FSW+) and another with lower (FSW−) frequency. For a weak flow, the frequency of the FSW+ (FSW−) increases (decreases) as the flow speed grows in both propagating and quasi-standing wave regimes. We show that the FSW+ and FSW− are subjected to the Kelvin–Helmholtz (KH) instability, and the threshold flow is greater (less than) the internal Alfvén speed for the FSW+ (FSW−). The presence of plasma flow results in modifying the period ratio P 1/2P 2 of the fundamental harmonic to the first overtone with P 1/2P 2 less (more) than 1 for the FSW+ (FSW−), and this effect degenerates in the straight waveguide limit. The sub-Alfvénic flow can prohibit resonant absorption of kink modes when the frequencies of the FSW+ and FSW− become out of the Alfvén continuum. It is also shown that in the static case and for a weak flow case, the FSW+ (FSW−) is interpreted as a vertically (horizontally) polarized kink mode, while for moderate flow, both modes have oblique polarization. We apply the developed theory to interpret the observational cases of kink oscillations in coronal loops with signatures of a siphon flow and the onset of KH instability induced by the blowout jet along a loop-shaped magnetic structure.

Effects of coronal rain on decayless kink oscillations of coronal loops

Decayless kink oscillations are ubiquitously observed in active region coronal loops with an almost constant amplitude for several cycles. Decayless kink oscillations of coronal loops triggered by coronal rain have been analyzed, but the impact of coronal rain formation in an already oscillating loop is unclear. As kink oscillations can help diagnose the local plasma conditions, it is important to understand how these are affected by coronal rain phenomena. In this study, we present the analysis of an event of coronal rain that occurred on 25 April 2014 and was simultaneously observed by Slit-Jaw Imager (SJI) on board Interface Region Imaging Spectrograph (IRIS) and Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). We investigated the oscillation properties of the coronal loop in AIA images before and after the appearance of coronal rain as observed by SJI. We find signatures of decayless oscillations before and after coronal rain at similar positions to those found during coronal rain. The individual cases show a greater amplitude and period during coronal rain. The mean period is increased by 1.3 times during coronal rain, while the average amplitude is increased by 2 times during rain, in agreement with the expected density increase from coronal rain. The existence of the oscillations in the same loop at the time of no coronal rain indicates the presence of a footpoint driver. The properties of the observed oscillations during coronal rain can result from the combined contribution of coronal rain and a footpoint driver. The oscillation amplitude associated with coronal rain is approximated to be 0.14 Mm. The properties of decayless oscillations are considerably affected by coronal rain, and without prior knowledge of coronal rain in the loop, a significant discrepancy can arise from coronal seismology with respect to the true values.

Comparison of damping models for kink oscillations of coronal loops

ABSTRACT Kink oscillations of solar coronal loops are of intense interest due to their potential for diagnosing plasma parameters in the corona. The accurate measurement of the kink oscillation damping time is crucial for precise seismological diagnostics, such as the transverse density profile, and for the determination of the damping mechanism. Previous studies of large-amplitude rapidly decaying kink oscillations have shown that both an exponential damping model and a generalized model (consisting of Gaussian and exponential damping patterns) fit observed damping profiles sufficiently well. However, it has recently been shown theoretically that the transition from the decaying regime to the decayless regime could be characterized by a superexponential damping model. In this work, we reanalyse a sample of decaying kink oscillation events, and utilize the Markov chain Monte Carlo Bayesian approach to compare the exponential, Gaussian–exponential, and superexponential damping models. It is found that in 7 out of 10 analysed oscillations, the preferential damping model is the superexponential one. In two events, the preferential damping is exponential, and in one it is Gaussian–exponential. This finding indicates the plausibility of the superexponential damping model. The possibility of a non-exponential damping pattern needs to be taken into account in the analysis of a larger number of events, especially in the estimation of the damping time and its associated empirical scalings with the oscillation period and amplitude, and in seismological inversions.

Traveling kink oscillations of coronal loops launched by a solar flare

Context. Kink oscillations, which are often associated with magnetohydrodynamic waves, are usually identified as transverse displacement oscillations of loop-like structures. However, the traveling kink oscillation evolving to a standing wave has rarely been reported. Aims. We investigate the traveling kink oscillation triggered by a solar flare on 2022 September 29. The traveling kink wave is then evolved to a standing kink oscillation of the coronal loop. Methods. The observational data mainly come from the Solar Upper Transition Region Imager (SUTRI), Atmospheric Imaging Assembly (AIA), and Spectrometer/Telescope for Imaging X-rays (STIX). In order to accurately identify the diffuse coronal loops, we applied a multi-Gaussian normalization (MGN) image processing technique to the extreme ultraviolet (EUV) image sequences at SUTRI 465 Å, AIA 171 Å, and 193 Å. A sine function within the decaying term and linear trend is used to extract the oscillation periods and amplitudes. With the aid of a differential emission measure analysis, the coronal seismology is applied to diagnose key parameters of the oscillating loop. At last, the wavelet transform is used to seek for multiple harmonics of the kink wave. Results. The transverse oscillations with an apparent decay in amplitude and nearly perpendicular to the oscillating loop are observed in the passbands of SUTRI 465 Å, AIA 171 Å, and 193 Å. The decaying oscillation is launched by a solar flare erupted close to one footpoint of coronal loops and then it propagates along several loops. Next, the traveling kink wave is evolved to a standing kink oscillation. The standing kink oscillation along one coronal loop has a similar period of ∼6.3 min at multiple wavelengths, and the decaying time is estimated at ∼9.6−10.6 min. Finally, two dominant periods of 5.1 min and 2.0 min are detected in another oscillating loop, suggesting the coexistence of the fundamental and third harmonics. Conclusions. First, we report the evolution of a traveling kink pulse to a standing kink wave along coronal loops that has been induced by a solar flare. We also detected a third-harmonic kink wave in an oscillating loop.

The probable excitation mechanism of kink oscillations of coronal loops

Oscillations in various structures of the solar atmosphere, such as transverse (kink) oscillations of coronal loops, can be used in seismology. Transvers kink oscillations of coronal loops are often accompanied by solar flares. Despite the intensive study of kink oscillations of coronal loops in recent years, the excitation mechanism of these oscillations are still not known. In this paper, we aim to clarify the excitation mechanisms of transverse oscillations of coronal loops. For this purpose, first 458 oscillation events were identified by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) during its first ten years (2010–2019) with the use of the Helioviewer, JHelioviewer and Heliophysics Events Knowledgebase (HEK). Then, the association of these oscillation events with probable mechanism for exciting the kink oscillations such as flares, lower coronal eruptions and plasma ejections, and coronal mass ejections bursts were listed. Finally, about 138 suitable kink oscillations out of 485 oscillations with high-amplitude, long oscillation period and visible through the naked eye that were accompanied with other probable excitation mechanism of kink oscillations, were selected. This statistical analysis of the transverse oscillation coronal loops showed that that 102 of these 138 oscillation events (74 %) were associated with lower coronal eruptions or plasma ejections. About 38 oscillations out of 138 transverse oscillations (27.5%) were associated with coronal mass ejections/eruption. Also, 65 events (47 %) were associated with flares. The required speed of hypothetical drivers of transverse oscillations were calculated. The magnitude values of calculated speeds for shock wave of flares were found to be lower than 500±100 km/s in 87% of the cases. Also, the magnitude values of speeds for lower coronal mass eruption/ejection were obtained to be lower than 500±125 km/s in 94% of the cases. The magnitude values of these speeds are acceptable for lower coronal mass eruption/ejection. But, such low speeds do not favor the association of the oscillation excitation with a shock wave of flares, as usually assumed. Also, statistical analysis of start time and time difference of hypothetical drivers of transverse oscillations showed that there is no clear correlation between them. The results of this study indicated that shock wave of flares cannot be the main cause of transverse oscillations of coronal loops. So, this analysis shows that the most probable excitation mechanism of the kink oscillations of coronal loops are eruptions or plasma ejections rather than the blast shock waves ignited by flares. ‎

Simultaneous Detection of Flare-related Decaying and Decayless Kink Oscillations Using Jerk-aware Motion Magnification

Kink oscillations of coronal loops are often influenced by external events and this results in various changes of the oscillations. Studying the changes can provide valuable information for understanding kink oscillations. Our observation focuses on a flare region acquired by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory spacecraft on 2016 March 23. There are a bunch of arched loops and an open loop near the region. However, their oscillations show very low amplitudes. So we used the jerk-aware motion method to magnify the weak oscillations. We found that before the flare onset at 02:59 UT, there were some large loops above the arched loops being raised rapidly. The properties of the weak oscillations show clear changes. On the one hand, the oscillations in the arched loops were decayless initially, but both their amplitude and period increased after 02:30 UT and before the flare onset. Once enhanced, the oscillations decayed with time. On the other hand, the oscillations in the open loop were nearly constant before and after 02:30 UT, but their period increased. This means that the changes in periods and amplitudes of oscillations are likely associated with the loops raised before the flare.

Investigation of the Oscillations in a Flare-productive Active Region

We investigate the oscillations in active region (AR) NOAA 12891, which produces a C2.0 three-ribbon flare accompanying a jet on 2021 November 2. Using the data from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, the 5 minutes decayless kink oscillations of coronal loops were detected and they are independent of the solar flare. Based on the observed oscillations and seismological diagnostics, we estimate that the Alfvén speed and magnetic field in these coronal loops are around 466 km s−1 and 7.6 G, respectively. Additionally, the flare-related jet shows its plasmoids with 1 minute periodicity same as the intensity fluctuation of nearby flare ribbon. The correlation between the intensity fluctuation of jet and that of flare ribbon indicates that their 1 minute oscillations should originate from the same reconnection process.

Study of the Impact of Coronal Rain on Kink Oscillations of Coronal Loops

AbstractCoronal rain occurs in thermally unstable coronal loops, and comprises cool plasma condensations, falling towards the solar surface, guided by the magnetic field. Sometimes the coronal rain clumps are seen to be subjected to transverse oscillations. The numerical simulations have indicated that coronal rain can onset kink oscillations in coronal loops and can affect the properties of oscillations. In this proceeding, we present the analysis of transverse oscillations in conjunction with coronal rain. Atmospheric Imaging Assembly (AIA) is used to examine the characteristics of coronal loop oscillation before and after coronal rain development. The analysis showed that the amplitude and period of oscillations are greater during coronal rain.

Long-term evolution of decayless kink oscillations of solar coronal loops

ABSTRACT Long-term evolution of instantaneous parameters of decayless kink oscillations of six solar coronal loops observed for longer than 2 h each is studied. The oscillations are analysed by processing sequences of 171 Å images obtained with the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) in the time interval from 2020 December till 2021 June, with the motion magnification technique. It is established that decayless kink oscillations could exist for more than 30 or 40 oscillation cycles. Neither the loop brightness nor instantaneous parameters of the oscillations show a monotonic increase or decrease during the oscillation. The observed instantaneous oscillation periods and amplitudes are found to vary randomly in time, with distributions around the mean values that resemble Gaussian profiles. Mean values of the oscillation periods and amplitudes are consistent with previous observations of this phenomenon. A power-law dependence of the oscillation period on the displacement amplitude is found, with the power-law index of 0.41 and with the 95 per cent confidence interval of [0.39, 0.71]. In general, we established the lack of correlation between instantaneous oscillation parameters and loop brightness. One exception is an event with relatively strong anticorrelation of the amplitude and the loop’s brightness, with the cross-correlation coefficient of about −0.81, but this effect requires a further study. Fourier power spectra of the envelopes of the time-evolving instantaneous amplitudes and periods are white noise, indicating that consecutive values of the instantaneous parameters are independent of each other. The results obtained provide an empirical ground for validating and comparing existing and future theoretical models of decayless kink oscillations of coronal loops.

Kink Oscillations of Coronal Loops

Kink oscillations of coronal loops, i.e., standing kink waves, is one of the most studied dynamic phenomena in the solar corona. The oscillations are excited by impulsive energy releases, such as low coronal eruptions. Typical periods of the oscillations are from a few to several minutes, and are found to increase linearly with the increase in the major radius of the oscillating loops. It clearly demonstrates that kink oscillations are natural modes of the loops, and can be described as standing fast magnetoacoustic waves with the wavelength determined by the length of the loop. Kink oscillations are observed in two different regimes. In the rapidly decaying regime, the apparent displacement amplitude reaches several minor radii of the loop. The damping time which is about several oscillation periods decreases with the increase in the oscillation amplitude, suggesting a nonlinear nature of the damping. In the decayless regime, the amplitudes are smaller than a minor radius, and the driver is still debated. The review summarises major findings obtained during the last decade, and covers both observational and theoretical results. Observational results include creation and analysis of comprehensive catalogues of the oscillation events, and detection of kink oscillations with imaging and spectral instruments in the EUV and microwave bands. Theoretical results include various approaches to modelling in terms of the magnetohydrodynamic wave theory. Properties of kink oscillations are found to depend on parameters of the oscillating loop, such as the magnetic twist, stratification, steady flows, temperature variations and so on, which make kink oscillations a natural probe of these parameters by the method of magnetohydrodynamic seismology.

Effects of External Flow on Resonant Absorption of Coronal Loop Kink Oscillations Driven by an External Fast Wave: Selective Excitation Problem

Abstract Resonant absorption is considered to be a crucial mechanism for the damping of the coronal loop oscillations and plasma heating. We study resonant absorption of the coronal loop kink oscillations excited by such external drivers as flares, assuming that there is an intermediate shear flow region surrounding the loop. We find that for long coronal loops resonant absorption can be highly enhanced or reduced depending sensitively on the magnitude and direction of the flow and the spatial extent of the flow region when the transitional layer is thin. For short coronal loops, high flow speed and a thick transitional layer are needed to have a substantial resonant absorption. We provide a potential picture to explain the results where the external Alfvén speed and phase speed of the wave are important parameters. These results imply that the transport of the external wave energy into the loop is significantly changed by the shear flow region, which may cause the selective excitation of the coronal loop oscillations.

Transverse oscillation of a coronal loop induced by a flare-related jet

Context. Kink oscillations in coronal loops are ubiquitous, and we apply the observed parameters of oscillations to estimate the magnetic field strength of the loops. Aims. In this work, we report our multiwavelength observations of the transverse oscillation of a large-scale coronal loop with a length of ≥350 Mm. The oscillation was induced by a blowout coronal jet, which was related to a C4.2 circular-ribbon flare (CRF) in active region 12434 on 2015 October 16. We aim to determine the physical parameters in the coronal loop, including the Alfvén speed and the magnetic field strength. Methods. The jet-induced kink oscillation was observed in extreme ultraviolet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). Line-of-sight magnetograms were observed by the Helioseismic and Magnetic Imager (HMI) on board the SDO. We took several slices along the loop to assemble time-distance diagrams and used an exponentially decaying sine function to fit the decaying oscillation. The initial amplitude, period, and damping time of kink oscillations were obtained. Coronal seismology of the kink mode was applied to estimate the Alfvén speed and the magnetic field strength in the oscillating loop. In addition, we measured the magnetic field of the loop through nonlinear force-free field (NLFFF) modeling using the flux rope insertion method. Results. The oscillation is most pronounced in AIA 171 and 131 Å. The oscillation is almost in phase along the loop with a peak initial amplitude of ∼13.6 Mm, meaning that the oscillation belongs to the fast standing kink mode. The oscillation lasts for ∼3.5cycles with an average period of ∼462 s and an average damping time of ∼976 s. The values of τ/P lie in the range of 1.5–2.5. Based on coronal seismology, the Alfvén speed in the oscillating loop is estimated to be ∼1210 km s−1. Two independent methods are applied to calculate the magnetic field strength of the loop, resulting in 30–43 G using coronal seismology and 21–23 G using NLFFF modeling. Conclusions. The magnetic field strength estimated using two different approaches are on the same order of magnitude, which confirms the reliability of coronal seismology by comparing with NLFFF modeling.

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 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.

Kink Oscillations of Coronal Loops with a Longitudinal Electric Current

Oscillations of coronal loops with electric currents from one base to another are studied. The energy of longitudinal currents can be a source of energy for loop flares (Alfven and Carlqvist, 1967). A simplified model of a loop in the form of a composite cylindrical magnetic tube containing a shell with a potential azimuthal magnetic field is considered for the theoretical study of oscillations of loops with longitudinal currents. The dispersion features of the tube natural kink oscillations are considered based on numerical calculations.

Simultaneous transverse oscillations of a coronal loop and a filament excited by a circular-ribbon flare

Aims. The aim of this study is to investigate the excitation of kink oscillations in coronal loops and filaments, by analyzing a C3.4 circular-ribbon flare associated with a blowout jet in active region 12434 on 2015 October 16. Methods. The flare was observed in ultraviolet and extreme-ultraviolet wavelengths by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory (SDO) spacecraft. The line-of-sight (LOS) magnetograms of the photosphere were observed by the Helioseismic and Magnetic Imager on board SDO. Soft X-ray fluxes of the flares in 0.5−4 and 1−8 Å were recorded by the GOES spacecraft. Results. The flare excited small-amplitude kink oscillation of a remote coronal loop. The oscillation lasted for ≥4 cycles without significant damping. The amplitude and period are 0.3 ± 0.1 Mm and 207 ± 12 s. Interestingly, the flare also excited transverse oscillation of a remote filament. The oscillation lasted for ∼3.5 cycles with decaying amplitudes. The initial amplitude is 1.7−2.2 Mm. The period and damping time are 437−475 s and 1142−1600 s. The starting times of simultaneous oscillations of coronal loop and filament were concurrent with the hard X-ray peak time. Though small in size and short in lifetime, the flare set off a chain reaction. It generated a bright secondary flare ribbon (SFR) in the chromosphere, remote brightening (RB) that was cospatial with the filament, and intermittent, jet-like flow propagating in the northeast direction. Conclusions. The loop oscillation is most probably excited by the flare-induced blast wave at a speed of ≥1300 km s−1. The excitation of the filament oscillation is more complicated. The blast wave triggers secondary magnetic reconnection far from the main flare, which not only heats the local plasma to higher temperatures (SFR and RB), but produces jet-like flow (i.e., reconnection outflow) as well. The filament is disturbed by the secondary magnetic reconnection and experiences transverse oscillation. These findings provide new insight into the excitation of transverse oscillations of coronal loops and filaments.

Oscillation and Evolution of Coronal Loops in a Dynamical Solar Corona

Observations have revealed two regimes of kink oscillations of coronal loops. Large amplitude oscillations excited by impulsive energy releases such as coronal mass ejections are characterised by their strong damping by resonant absorption. Lower amplitude oscillations may also be excited and sustained by the ubiquitous motions present in the corona and so are characterised as being decayless. We perform numerical simulations to study the oscillation and evolution of coronal loops in a dynamical environment. We investigate the observational signatures of kink oscillations and the Kelvin-Helmholtz instability in terms of high-resolution seismological and spatial data analysis techniques. We find that low amplitude kink oscillations are capable of generating significant changes in the loop profile which can affect estimates of the transverse loop inhomogeneity based on seismological and forward modelling methods. The disparity between methods may be indicative of nonlinear evolution of coronal loops. The influence on forward modelling estimates could also account for previous observational evidence favouring loops having wider inhomogeneous layers.

Transverse coronal loop oscillations excited by homologous circular-ribbon flares

Aims. We report our multiwavelength observations of two homologous circular-ribbon flares in active region 11991 on 2014 March 5, focusing on the transverse oscillations of an extreme-ultraviolet (EUV) loop excited by the flares. Methods. The flares were observed in ultraviolet and EUV wavelengths by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory spacecraft. These flares were also observed in Hα line center by the 1 m New Vacuum Solar Telescope. Soft X-ray fluxes of the flares in 0.5–4 and 1–8 Å were recorded by the GOES spacecraft. Results. The transverse oscillations are of fast standing kink mode. The first-stage oscillation triggered by the C2.8 flare is decayless with lower amplitudes (310–510 km). The periods (115–118 s) in different wavelengths are nearly the same, indicating coherent oscillations. The magnetic field of the loop is estimated to be 65–78 G. The second-stage oscillation triggered by the M1.0 flare is decaying with larger amplitudes (1250–1280 km). The periods decrease from 117 s in 211 Å to 70 s in 171 Å, implying a decrease of loop length or an implosion after a gradual expansion. The damping time, which is 147–315 s, increases with the period, so that the values of τ/P are close to each other in different wavelengths. The thickness of the inhomogeneous layer is estimated to be ∼0″​​​.45 under the assumption of resonant absorption. Conclusions. This is the first observation of the excitation of two kink-mode loop oscillations by two sympathetic flares. The results are important to understand the excitation of kink oscillations of coronal loops and hence the energy balance in the solar corona. Our findings also validate the prevalence of significantly amplified amplitudes of oscillations by successive drivers.

A Longitudinally Asymmetrical Kink Oscillation of Coronal Loop Caused by a Diagonally Placed Flare below the Loop System

Abstract Although fast kink oscillations of coronal loops have been extensively studied for decades, details about their excitation, evolution, and damping remain elusive. Here, we present, for the first time, a longitudinally asymmetrical fast kink oscillation of a coronal loop that is excited by a GOES C-class flare located diagonally below the loop system. In this case, a damping-like phase and a growing-like phase are successively observed after the flare in different loop segments that are far from and close to the flare site, respectively. The investigation provides us with a new and valuable clue for the widely observed distinct deviations of fast kink oscillations from the sinusoidal pattern, especially for the local damping-like or growing-like phases associated with diagonally placed excitation sources, by illuminating a probable effect of the diagonally placed excitation source.

The Effect of Cooling on Driven Kink Oscillations of Coronal Loops

Ever since their detection two decades ago, standing kink oscillations in coronal loops have been extensively studied both observationally and theoretically. Almost all driven coronal loop oscillations (e.g., by flares) are observed to damp through time often with Gaussian or exponential profiles. Intriguingly, however, it has been shown theoretically that the amplitudes of some oscillations could be modified from Gaussian or exponential profiles if cooling is present in the coronal loop systems. Indeed, in some cases the oscillation amplitude can even increase through time. In this article, we analyse a flare-driven coronal loop oscillation observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA) in order to investigate whether models of cooling can explain the amplitude profile of the oscillation and whether hints of cooling can be found in the intensity evolution of several SDO/AIA filters. During the oscillation of this loop system, the kink mode amplitude appears to differ from a typical Gaussian or exponential profile with some hints being present that the amplitude increases. The application of cooling coronal loop modelling allowed us to estimate the density ratio between the loop and the background plasma, with a ratio of between 2.05-2.35 being returned. Overall, our results indicate that consideration of the thermal evolution of coronal loop systems can allow us to better describe oscillations in these structures and return more accurate estimates of the physical properties of the loops (e.g., density, scale height, magnetic field strength).

Catalog of Decaying Kink Oscillations of Coronal Loops in the 24th Solar Cycle

Catalog of Decaying Kink Oscillations of Coronal Loops in the 24th Solar Cycle