MHD Seismology of a Coronal Loop System by the First Two Modes of Standing Kink Waves

Abstract

We report the observation of the first two harmonics of the horizontally polarized kink waves excited in a coronal loop system lying at south-east of AR 11719 on 2013 April 11. The detected periods of the fundamental mode ($P_1$), its first overtone ($P_2$) in the northern half, and that in the southern one are $530.2\pm 13.3$, $300.4\pm 27.7$, and $334.7\pm 22.1$ s, respectively. The periods of the first overtone in the two halves are the same considering uncertainties in the measurement. We estimate the average electron density, temperature, and length of the loop system as $(5.1\pm 0.8)\times 10^8$ cm${}^{-3}$, $0.65\pm 0.06$ MK, and $203.8\pm 13.8$ Mm, respectively. As a zeroth order estimation, the magnetic field strength, $B=8.2\pm 1.0$ G, derived by the coronal seismology using the fundamental kink mode matches with that derived by a potential field model. The extrapolation model also shows the asymmetric and nonuniform distribution of the magnetic field along the coronal loop. Using the amplitude profile distributions of both the fundamental mode and its first overtone, we observe that the antinode positions of both the fundamental mode and its first overtone shift towards the weak field region along the coronal loop. The results indicate that the density stratification and the temperature difference effects are larger than the magnetic field variation effect on the period ratio. On the other hand, the magnetic field variation has a greater effect on the eigenfunction of the first overtone than the density stratification does for this case.

24 pages, 6 figures, 1 table, accepted for publication in ApJ

References in corpus (3)

• First Evidence of Coexisting EIT Wave and Coronal Moreton Wave from SDO/AIA Observations
• Observation of multiple sausage oscillations in cool postflare loop
• Longitudinal oscillations in density stratified and expanding solar waveguides

Cited by in corpus (15)

• Kink oscillations of coronal loops
• Multiwavelength observations of a partially eruptive filament on 2011 September 8
• Mapping the magnetic field in the solar corona through magnetoseismology
• Transverse coronal loop oscillations excited by homologous circular-ribbon flares
• Kink Oscillations in Solar Coronal Loops with Elliptical Cross-Sections. I. the linear regime
• Traveling kink oscillations of coronal loops launched by a solar flare
• On Modeling the Kelvin--Helmholtz Instability in Solar Atmosphere
• Transverse oscillation of a coronal loop induced by a flare-related jet
• Prominence Oscillations activated by an EUV wave
• Extreme-Ultraviolet Wave and Accompanying Loop Oscillations
• Filament Eruption Driving EUV Loop Contraction then Expansion above a Stable Filament
• Kinematics and Energetics of the EUV Waves on 11 April 2013
• Temporal evolution of oscillating coronal loops
• Transverse vertical oscillations during the contraction and expansion of coronal loops
• Modeling the Excitation, Propagation and Damping of Quasi-Periodic Fast Magnetosonic Waves in Realistic Coronal Active Region Magnetic Field Structures