Oscillation and Evolution of Coronal Loops in a Dynamical Solar Corona

Nonlinear Damping of Standing Kink Waves Computed With Elsässer Variables

“…Continuing on the Monte Carlo process for re-creating the observed data points, our method offers perspective on a Bayesian inference of loop parameters (see e.g. Verwichte et al 2013;Arregui et al 2013a;Pascoe et al 2020) by finding the best statistical match between the two data clouds. This has the potential to seismologically determine the radii of coronal loops, the substructure of the loop, their density contrast distribution and the oscillation amplitude distribution.…”

Coronal Seismology Using Damping of Propagating Kink Waves

“…There is ample observational evidence for the nonexponential or Gaussian damping regime for kink oscillations (De Moortel et al 2002;Goddard et al 2016;Pascoe et al 2016b;Morton & Mooroogen 2016), and it has also been shown in linear (Ruderman & Terradas 2013;Pascoe et al 2019a) and nonlinear Pagano et al 2018;Goddard et al 2018;Pascoe et al 2020) numerical models of standing kink waves. Observations analyzed using both the Gaussian and exponential damping regimes have been used to perform seismological inferences of coronal loop density profiles (Pascoe et al 2016a(Pascoe et al , 2017a(Pascoe et al , 2017c(Pascoe et al , 2018.…”

“…In particular, ò is defined to have limits of [ ] 0, 2 . Figure 6 of Pascoe et al (2020) shows that there is a preference toward higher values, but this is based on the statistical study of loops observed with SDO/AIA (Goddard et al 2017). It may be the case that these loops typically have a higher density contrast ratio than those observed with CoMP and that the bias toward larger ò arises due to the KHI, which is stronger for larger ζ.…”

“…This was applied by Goddard et al (2017) in a statistical study of 233 loops. Pascoe et al (2020) demonstrated that the distribution of layer widths covers the full range of [ ]  = 0, 2 , but favors higher values. This is consistent with the evolution of the loop density profile due to the Kelvin-Helmholtz instability (KHI; e.g., Terradas et al 2008;Soler et al 2010;Antolin et al 2014Antolin et al , 2017.…”

“…We note that this correction does not include nonlinear effects such as the KHI (e.g., Browning & Priest 1984;Ofman et al 1994;Antolin et al 2014). The structures generated by the KHI can increase the damping rate due to resonant absorption (Pascoe et al 2020), which has been detected in an observation of a loop perturbed by two separate flaring releases (Pascoe et al 2020a). Nonlinear damping can persist in the limit ζ → 1 in the case of standing waves (Van Doorsselaere et al 2021), but not for the propagating waves (Van Doorsselaere et al 2020a) considered in this paper.…”