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Quasi-periodic intensity disturbances propagating upward along the coronal structure have been extensively studied using EUV imaging observations from SOHO/EIT and TRACE. They were interpreted as either slow mode magnetoacoustic waves or…

Solar and Stellar Astrophysics · Physics 2012-01-26 Tongjiang Wang , Leon Ofman , Joseph M. Davila

We report the first observation of multiple-periodic propagating disturbances along a fan-like coronal structure simultaneously detected in both intensity and Doppler shift in the Fe XII 195 A line with the EUV Imaging Spectrometer (EIS)…

Solar and Stellar Astrophysics · Physics 2010-11-11 T. J. Wang , L. Ofman , J. M. Davila , J. T. Mariska

Recent studies of a flaring loop oscillation event on 2013 December 28 observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) have revealed the suppression of thermal conduction and significant…

Solar and Stellar Astrophysics · Physics 2020-08-10 Tongjiang Wang , Leon Ofman

We apply a new method to determine the magnetic field in coronal loops using observations of coronal loop oscillations. We analyze seven Doppler shift oscillation events detected by SUMER in the hot flare line Fe XIX to obtain oscillation…

Astrophysics · Physics 2008-11-26 Tongjiang Wang , Davina E. Innes , Jiong Qiu

We perform multiwavelength time-distance analysis of a fan loop system anchored in an isolated sunspot region AR 12553. The active region was observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We measure…

Solar and Stellar Astrophysics · Physics 2020-07-01 Aishawnnya Sharma , Durgesh Tripathi , Robertus Erdelyi , G. R. Gupta , G. A. Ahmed

Spectroscopic and stereoscopic imaging observations of slow magnetoacoustic wave propagation within a coronal loop are investigated to determine the decay length scale of the slow magnetoacoustic mode in three dimensions and the density…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. S. Marsh , I. De Moortel , R. W. Walsh

In order to better understand the possibility of coronal heating by MHD waves, we analyze Fe xii 195.12{\AA} data observed with EUV Imaging Spectrometer (EIS) onboard Hinode. We performed a Fourier analysis of EUV intensity and Doppler…

Solar and Stellar Astrophysics · Physics 2015-05-19 Naomasa Kitagawa , Takaaki Yokoyama , Shinsuke Imada , Hirohisa Hara

The effect of temperature inhomogeneity on the periods, their ratios (fundamental vs. first overtone), and the damping times of the standing slow modes in gravitationally stratified solar coronal loops are studied. The effects of optically…

Solar and Stellar Astrophysics · Physics 2015-06-05 A. Abedini , H. Safari , S. Nasiri

We simulate transverse oscillations in radiatively cooling coronal loops and forward-model their spectroscopic and imaging signatures, paying attention to the influence of background emission. The transverse oscillations are driven at one…

Solar and Stellar Astrophysics · Physics 2021-12-01 Mijie Shi , Tom Van Doorsselaere , Patrick Antolin , Bo Li

We studied long duration flare observed with Nobeyama Radioheliograph at frequencies 17 and 34 GHz and with Ramaty High Energy Solar Spectroscopic Imager at 25-50 keV. We found that microwave and hard X-ray emission variation contain…

Solar and Stellar Astrophysics · Physics 2011-10-07 Veronika Reznikova , Kiyoto Shibasaki

We report high resolution observations from the SDO/AIA of intensity oscillations in a hot, T~8-10 MK, loop. The AIA images show a large coronal loop that was rapidly heated following plasma ejection from one of the loop's footpoints. A…

Solar and Stellar Astrophysics · Physics 2014-09-16 Pankaj Kumar , D. E. Innes , B. Inhester

We study the propagation properties of slow magneto-acoustic waves in a multi-thermal coronal loop using a 3D MHD model, for the first time. A bundle of 33 vertical cylinders, each of 100{\,}km radius, randomly distributed over a circular…

Solar and Stellar Astrophysics · Physics 2024-06-06 S. Krishna Prasad , T. Van Doorsselaere

Oscillations in coronal loops are usually interpreted in terms of uncoupled magnetohydrodynamic (MHD) waves. Examples of these waves are standing transverse motions, interpreted as the kink MHD modes, and propagating slow modes, commonly…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. Terradas , J. Andries , E. Verwichte

We studied waves seen during the class C1.9 flare that occurred in Active Region NOAA 11272 on SOL2011-08-17. We found standing waves with periods in the 9- and 19-minute band in six extreme ultraviolet (EUV) wavelengths of the SDO/AIA…

Solar and Stellar Astrophysics · Physics 2016-11-29 S. M. Conde Cuellar , J. E. R. Costa , C. E. Cedeño Montaña

Propagating disturbances are often observed in active region fan-like coronal loops. They were thought to be due to slow mode MHD waves based on some of the observed properties. But the recent studies involving spectroscopy indicate that…

Solar and Stellar Astrophysics · Physics 2015-11-11 S. Mandal , T. Samanta , D. Banerjee , S. Krishna Prasad , L. Teriaca

Low-amplitude Doppler-shift oscillations have been observed in coronal emission lines in a number of active regions with the EUV Imaging Spectrometer (EIS) on the Hinode satellite. Both standing and propagating waves have been detected and…

Solar and Stellar Astrophysics · Physics 2015-05-18 John T. Mariska , K. Muglach

Context. Slow waves in solar coronal loops are strongly damped. The current theory of damping by thermal conduction cannot explain some observational features.\n Aims. We investigate the propagation of slow waves in a coronal loop built up…

Solar and Stellar Astrophysics · Physics 2024-01-19 Tom Van Doorsselaere , S. Krishna Prasad , Vaibhav Pant , Dipankar Banerjee , Alan Hood

A statistical model is used to determine how stochastic fluctuations in the intensities of orthogonal polarization modes contribute to the modulation and depolarization of pulsar radio emission. General expressions for the distributions of…

High Energy Astrophysical Phenomena · Physics 2023-12-19 M. M. McKinnon

Context. QPPs are usually detected as spatial displacements of coronal loops in imaging observations or as periodic shifts of line properties in spectroscopic observations. They are often applied for remote diagnostics of magnetic fields…

Solar and Stellar Astrophysics · Physics 2018-09-26 D. Li , D. Yuan , Y. N. Su , Q. M. Zhang , W. Su , Z. J. Ning

Recurrent and propagating intensity perturbations are frequently observed in extreme ultraviolet (EUV) channels along coronal fan loops above sunspots, and these perturbations are suggested to be slow magnetoacoustic waves. Numerous studies…

Solar and Stellar Astrophysics · Physics 2025-02-26 Junwei Zhao , Tongjiang Wang , Ruizhu Chen