Excitation of Multiperiodic Kink Motions in Solar Flare Loops: Possible Application to Quasiperiodic Pulsations

• Published in: Astrophysical journal. Letters Vol. 943; no. 2; p. L19
• Main Authors: Shi, Mijie, Li, Bo, Chen, Shao-Xia, Guo, Mingzhe, Yuan, Shengju
• Format: Journal Article
• Language: English
• Published: Austin The American Astronomical Society 01.02.2023; IOP Publishing
• Subjects: Fluid flow; Magnetohydrodynamic waves; Magnetohydrodynamical simulations; Magnetohydrodynamics; Microwave emission; Oscillations; Periodicities; Perturbation; Radio telescopes; Solar corona; Solar coronal radio emission; Solar flares; Telescopes
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/acb3c6

Abstract Magnetohydrodynamic (MHD) waves are often invoked to interpret quasiperiodic pulsations (QPPs) in solar flares. We study the response of a straight flare loop to a kink-like velocity perturbation using three-dimensional MHD simulations and forward model the microwave emissions using the fast gyrosynchrotron code. Kink motions with two periodicities are simultaneously generated, with the long-period component ( P L = 57 s) being attributed to the radial fundamental kink mode and the short-period component ( P S = 5.8 s) to the first leaky kink mode. Forward modeling results show that the two-periodic oscillations are detectable in the microwave intensities for some lines of sight. Increasing the beam size to (1″) 2 does not wipe out the microwave oscillations. We propose that the first leaky kink mode is a promising candidate mechanism to account for short-period QPPs. Radio telescopes with high spatial resolutions can help distinguish between this new mechanism and such customary interpretations as sausage modes.