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Three dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington Rotations (CR 2054$-$2153) during 2007/03$-$2014/08 using the spherically symmetric method from polarized white-light observations…

Solar and Stellar Astrophysics · Physics 2017-07-25 Tongjiang Wang , Nelson L. Reginald , Joseph M. Davila , O. Chris St. Cyr , William T. Thompson

Coronal loops generally trace magnetic lines of force in the upper solar atmosphere. Understanding the loop morphology and its temporal evolution has implications for coronal heating models that rely on plasma heating due to reconnection at…

Solar and Stellar Astrophysics · Physics 2025-01-29 B. Ram , L. P. Chitta , S. Mandal , H. Peter , F. Plaschke

Recent analyses of helioseismological observations seem to suggest the presence of two new phenomena connected with the dynamics of the solar convective zone. Firstly, there are present torsional oscillations with periods of about 11 years,…

Astrophysics · Physics 2009-10-31 Eurico Covas , Reza Tavakol , David Moss

Despite decades of studying the Sun, the coronal heating problem remains unsolved. One fundamental issue is that we do not know the spatial scale of the coronal heating mechanism. At a spatial resolution of 1000 km or more it is likely that…

Solar and Stellar Astrophysics · Physics 2012-06-07 David H. Brooks , Harry P. Warren , Ignacio Ugarte-Urra

The total solar eclipse of August 21st, 2017 was observed with a Digital Single Lens Reflex (DSLR) camera equipped with a linear polarizing filter. A method was developed to combine images acquired with 15 different exposure times (from…

Solar and Stellar Astrophysics · Physics 2020-12-09 Alessandro Bemporad

Propagating slow magneto-acoustic waves are commonly observed in different coronal structures but are most prominent in active region fan loops. Their rapid damping with damping lengths of the order of a wavelength has been investigated in…

Solar and Stellar Astrophysics · Physics 2025-06-09 Suraj K. Tripathy , S. Krishna Prasad , D. Banerjee

Thermal non-equilibrium (TNE) is a phenomenon that can occur in solar coronal loops when the heating is quasi-constant and highly-stratified. Under such heating conditions, coronal loops undergo cycles of evaporation and condensation. The…

Solar and Stellar Astrophysics · Physics 2019-12-25 C. Froment , P. Antolin , V. M. J. Henriques , P. Kohutova , L. H. M. Rouppe van der Voort

Evolution of a coronal loop in response to an impulsive energy release is numerically modelled. It is shown that the loop density evolution curves exhibit quasi-periodic perturbations with the periods given approximately by the ratio of the…

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

This study proposes an enhancement to the existing method for detecting Solar Active Regions (ARs). Our technique tracks ARs using images from the Atmospheric Imaging Assembly (AIA) of NASA's Solar Dynamics Observatory (SDO). It involves a…

Solar and Stellar Astrophysics · Physics 2024-08-27 Irewola Aaron Oludehinwa , Andrei Velichko , Maksim Belyaev , Olasunkanmi I. Olusola

We present results of a global survey of single-pixel intensity power spectra from a 12-hour time period on 26 June 2013 in a 1600x1600 pixel region from four channels of the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly…

Solar and Stellar Astrophysics · Physics 2019-01-29 Karl Battams , Brendan M. Gallagher , Robert S. Weigel

We aim to study the influence of radiative cooling on the standing kink oscillations of a coronal loop. Using the FLASH code, we solved the 3D ideal magnetohydrodynamic equations. Our model consists of a straight, density enhanced and…

Solar and Stellar Astrophysics · Physics 2015-10-30 N. Magyar , T. Van Doorsselaere , A. Marcu

To adequately constrain the frequency of energy deposition in active region cores in the solar corona, systematic comparisons between detailed models and observational data are needed. In this paper, we describe a pipeline for forward…

Solar and Stellar Astrophysics · Physics 2019-07-31 W. T. Barnes , S. J. Bradshaw , N. M. Viall

The eleven year solar cycle is known to affect the global modes of solar acoustic oscillations. In particular, p mode frequencies increase with solar activity. We propose a new method to detect the solar cycle from the p-mode…

Solar and Stellar Astrophysics · Physics 2023-12-05 Valeriy Vasilyev , Laurent Gizon

We analyse the temporal evolution of the inclination component of the magnetic field vector for the penumbral area of 25 isolated sunspots. Compared to previous works, the use of data from the HMI instrument aboard the SDO observatory…

Solar and Stellar Astrophysics · Physics 2020-03-11 A. B. Griñón-Marín , A. Pastor Yabar , H. Socas-Navarro , R. Centeno

This study presents a nonlinear signal processing method for accurate radar-based heartbeat interval estimation by exploiting the periodicity of higher-order harmonics inherent in heartbeat signals. Unlike conventional approaches that…

Signal Processing · Electrical Eng. & Systems 2025-07-29 Kohei Shimomura , Chi-Hsuan Lee , Takuya Sakamoto

Recent SECCHI COR2 observations on board STEREO-A spacecraft have detected density structures at a distance of 2.5--15~R propagating with periodicity of about 90~minutes. The observations show that the density structures probably formed in…

Solar and Stellar Astrophysics · Physics 2017-04-26 O. S. Pylaev , T. V. Zaqarashvili , A. I. Brazhenko , V. N. Melnik , A. Hanslmeier , M. Panchenko

We present an empirical model based on the visible area covered by coronal holes close to the central meridian in order to predict the solar wind speed at 1 AU with a lead time up to four days in advance with a 1hr time resolution. Linear…

Solar and Stellar Astrophysics · Physics 2015-06-03 T. Rotter , A. M. Veronig , M. Temmer , B. Vrsnak

For the purpose of investigating the differential rotation of the solar corona, we analyzed ultraviolet (UV) spectral line observations acquired on both the east and west limbs at 1.7 $R_{\odot}$ by SOHO/UVCS during the solar minimum…

Solar and Stellar Astrophysics · Physics 2020-11-25 S. Mancuso , S. Giordano , D. Barghini , D. Telloni

Spatially unresolved observations show that the cooling phase in solar flares can be much longer than theoretical models predict. It has not yet been determined whether this is also the case for different subregions within the flare…

Solar and Stellar Astrophysics · Physics 2024-06-21 Malte Bröse , Alexander Warmuth , Taro Sakao , Yang Su

We investigate quasi-periodic coronal pulsations during the decay phase of an X 3.2 class flare on 14 May 2013, using soft X-ray data from the RHESSI satellite. Periodogram analyses of soft X-ray light curves show that 53 s and 72 s periods…

Solar and Stellar Astrophysics · Physics 2016-01-20 Partha Chowdhury , A. K. Srivastava , B. N. Dwivedi , Robert Sych , Y. -J. Moon
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