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We investigate the nature of transverse kink oscillations of loops expanding through the solar corona and how can oscillations be used to diagnose the plasma parameters and the magnetic field. In particular, we aim to analyse how the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Istvan Ballai , Beniamin Orza

Quasi-periodic pulsations (QPPs) are a common feature of impulsive solar flare emissions, yet their driving mechanism(s) remain unresolved. We study long-period (3.4 min) QPPs in the M3.7 flare on Feb 24, 2023, using SDO/AIA and Solar…

Solar and Stellar Astrophysics · Physics 2025-06-05 Stefan Purkhart , Hannah Collier , Laura A. Hayes , Astrid M. Veronig , Miho Janvier , Säm Krucker

Using the ULTRASPEC instrument mounted on the 2.4-m Thai National Telescope, we observed two large flares, each with a total energy close to 10^34 erg with sub-second cadence. A combination of a wavelet analysis, a Fourier transform plus an…

Low-frequency longitudinal oscillations of a flaring coronal loop are studied numerically. In the recent work of Nakariakov et al., Astron. and Astrophys., 414, L25-L28 (2004) it has been shown that the time dependences of density and…

Astrophysics · Physics 2009-11-10 D. Tsiklauri , V. M. Nakariakov , T. D. Arber , M. J. Aschwanden

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…

Quasi-periodic pulsations (QPP) are common in solar flares and are now regularly observed in stellar flares. We present the detection of two different types of QPP signals in the thermal emission light curves of the X9.3 class solar flare…

Solar and Stellar Astrophysics · Physics 2018-05-02 Dmitrii Y. Kolotkov , Chloe E. Pugh , Anne-Marie Broomhall , Valery M. Nakariakov

Quasi-periodic pulsations (QPP) seen in the time derivative of the GOES soft X-ray light curves are analyzed for the near-limb X3.2 event on 14 May 2013. The pulsations are apparent for a total of at least two hours from the impulsive phase…

Radio observations of solar flares often reveal various periodic or quasi-periodic oscillations. Most likely, these oscillations are caused by magnetohydrodynamic (MHD) oscillations of flaring loops which modulate the emission.…

Solar and Stellar Astrophysics · Physics 2015-06-24 Alexey Kuznetsov , Tom Van Doorsselaere , Veronika Reznikova

We investigate the long-term evolution of an initially buoyant magnetic flux tube emerging into a gravitationally-stratified coronal hole environment and report on the resulting oscillations and outflows. We perform 2.5D nonlinear numerical…

Solar and Stellar Astrophysics · Physics 2012-04-02 J. A. McLaughlin , G. Verth , V. Fedun , R. Erdélyi

We investigate quasi-periodic pulsations (QPPs) of high-energy nonthermal emissions from an X9.3 flare (SOL2017-Sep-06T11:53), the most powerful flare since the beginning of solar cycle 24. The QPPs are identified as a series of regular and…

Solar and Stellar Astrophysics · Physics 2020-01-15 D. Li , D. Y. Kolotkov , V. M. Nakariakov , L. Lu , Z. J. Ning

Twisted magnetic fields should be ubiquitous in flare-producing active regions where the magnetic fields are strongly non-potential. It has been shown that reconnection in helical magnetic coronal loops results in plasma heating and…

Solar and Stellar Astrophysics · Physics 2016-01-20 R. F. Pinto , M. Gordovskyy , P. K. Browning , N. Vilmer

Twisted coronal loops should be ubiquitous in the solar corona. Twisted magnetic fields contain excess magnetic energy, which can be released during magnetic reconnection, causing solar flares. The aim of this work is to investigate…

Solar and Stellar Astrophysics · Physics 2015-01-27 Mykola Gordovskyy , Philippa Browning , Eduard Kontar , Nicolas Bian

Quasi-periodic pulsations (QPP) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and…

Solar and Stellar Astrophysics · Physics 2016-08-24 Laura A. Hayes , Peter T. Gallagher , Brian R. Dennis , Jack Ireland , Andrew R. Inglis , Daniel F. Ryan

Decayless kink oscillations are frequently observed in solar coronal loops and are considered potential contributors to coronal heating. Despite the ubiquity of this wave phenomenon, its driving mechanism remains unclear. Studies to derive…

Solar and Stellar Astrophysics · Physics 2026-03-04 Sudip Mandal , Cosima Breu , Hardi Peter

Decaying pulsations have been simultaneously detected in the low-energy X-rays of solar/stellar flares, which are supposed to be associated with standing slow magnetoacoustic or kink-mode waves. The physical mechanism behind rapidly…

Solar and Stellar Astrophysics · Physics 2025-10-21 Dong Li , Jianping Li , Haisheng Ji

We report quasi-periodic pulsations (QPPs) with double periods during three solar flares (viz. SOL2011-Feb-15T01:44, SOL2011-Sep-25T04:31, SOL2012-May-17T01:25). The flare QPPs were observed from light curves in Ly$\alpha$, hard X-ray (HXR)…

Solar and Stellar Astrophysics · Physics 2021-09-08 Lei Lu , Dong Li , Zongjun Ning , Li Feng , Weiqun Gan

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…

Solar and Stellar Astrophysics · Physics 2019-05-31 C. J. Nelson , A. A. Shukhobodskiy , R. Erdélyi , M. Mathioudakis

We present a case study of the solar flare (SOL2001-10-02T17:31) that showed quasi-periodic pulsations (QPPs) in hard X-rays with two simultaneously excited periods, P_1 = 26-31 s and P_2 = 110 s. Complete evolution of the flare recorded by…

Solar and Stellar Astrophysics · Physics 2014-12-09 M. Tomczak , Z. Szaforz

A quantitative study of the observable radio signatures of the sausage, kink, and torsional MHD oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the…

Solar and Stellar Astrophysics · Physics 2015-06-03 George Mossessian , Gregory D. Fleishman

Solar flares are among the most powerful and disruptive events in our solar system, however the physical mechanisms driving and transporting this energetic release are not fully understood. An important signature associated with flare…