Generating transverse loop oscillations through a steady-flow driver

Abstract

In recent years, the decay-less regime of standing transverse oscillations in coronal loops has been the topic of many observational and numerical studies, focusing on their physical characteristics, as well as their importance for coronal seismology and wave heating. However, no definitive answer has yet been given on the driving mechanism behind these oscillations, with most studies focusing on the use of periodic footpoint drivers as a means to excite them. In this paper, our goal is to explore the concept of these standing waves being self-sustained oscillations, driven by a constant background flow. To that end, we use the PLUTO code, to perform $3$D magnetohydrodynamic simulations of a gravitationally stratified straight flux tube in a coronal environment, in the presence of a weak flow around the loop, perpendicular to its axis. Once this flow is firmly set up, a transverse oscillation is initiated, dominated by the fundamental kink mode of a standing wave, while the existence of a second harmonic is revealed, with a frequency ratio to the fundamental mode near the observed ones in decay-less oscillations. The presence of vortex shedding is also established in our simulations, which is connected to the "slippery" interaction between the oscillator and its surrounding plasma. We thus present a proof-of-concept of a self-oscillation in a coronal loop, and we propose it as a mechanism that could interpret the observed decay-less transverse oscillations of coronal loops.

7 pages, 3 figures

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Cited by in corpus (21)

• Kink oscillations of coronal loops
• Decayless oscillations in solar coronal bright points
• What drives decayless kink oscillations in active region coronal loops on the Sun?
• A Statistical Study of Short-period Decayless Oscillations of Coronal Loops in an Active Region
• Weak damping of propagating MHD kink waves in the quiescent corona
• Two-Spacecraft Detection of Short-period Decayless Kink Oscillations of Solar Coronal Loops
• Transverse loop oscillations via vortex shedding: a self oscillating process
• A Statistical Investigation of Decayless Oscillations in Small-scale Coronal Loops Observed by Solar Orbiter/EUI
• Cut-off of transverse waves through the solar transition region
• 30-min Decayless Kink Oscillations in a Very Long Bundle of Solar Coronal Plasma Loops
• Kink Oscillation of a Flux Rope During a Failed Solar Eruption
• Excitation and evolution of coronal oscillations in self-consistent 3D radiative MHD simulations of the solar atmosphere
• Decayless oscillations in 3D coronal loops excited by a power-law driver
• Do Periods of Decayless Kink Oscillations of Solar Coronal Loops Depend on Noise?
• Forward Modeling of Simulated Transverse Oscillations in Coronal Loops and the Influence of Background Emission
• Characteristics and Energy Flux Distributions of Decayless Transverse Oscillations Depending on Coronal Regions
• Kelvin-Helmholtz instability and heating in oscillating loops perturbed by power-law transverse wave drivers
• Coronal kink oscillations and photospheric driving: combining SolO/EUI and SST/CRISP high-resolution observations
• Effects of external flow on resonant absorption of coronal loop kink oscillations driven by an external fast wave: Selective excitation problem
• Polarization of decayless kink oscillations in a 3D MHD coronal loop model
• Spectra of standing kink waves in loops and the effects of the lower solar atmosphere