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Related papers: Coronal energy release by MHD avalanches II. EUV l…

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Erupting magnetic flux ropes (MFRs) play a crucial role in producing solar flares. However, the formation of erupting MFRs in complex coronal magnetic configurations and their subsequent evolution in the flaring events are not fully…

Solar and Stellar Astrophysics · Physics 2023-08-30 Avijeet Prasad , Sanjay Kumar , Alphonse C. Sterling , Ronald L. Moore , Guillaume Aulanier , R. Bhattacharyya , Qiang Hu

There is ample evidence of twisted magnetic structures in the solar corona. This motivates us to consider the magnetic twist as the cause of Alfven frequency continuum in the coronal loops, which can support the resonant absorption as a…

Solar and Stellar Astrophysics · Physics 2016-08-18 Zanyar Ebrahimi , Kayoomars Karami

Adopting the MPI-AMRVAC code, we present a 2.5-dimensional magnetohydrodynamic (MHD) simulation, which includes thermal conduction and radiative cooling, to investigate the formation and evolution of the coronal rain phenomenon. We perform…

Solar and Stellar Astrophysics · Physics 2022-03-09 Xiaohong Li , Rony Keppens , Yuhao Zhou

We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along…

Solar and Stellar Astrophysics · Physics 2018-03-26 Ioannis Kontogiannis , Costis Gontikakis , Georgia Tsiropoula , Kostas Tziotziou

We present new measurements of the dependence of the Extreme Ultraviolet radiance on the total magnetic flux in active regions as obtained from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager on board the…

Solar and Stellar Astrophysics · Physics 2017-09-20 Ignacio Ugarte-Urra , Harry P. Warren , Lisa A. Upton , Peter R. Young

We investigate the evolution of coronal loop emission in the context of the coronal magnetic field topology. New modeling techniques allow us to investigate the magnetic field structure and energy release in active regions. Using these…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. -Y. Lee , Graham Barnes , K. D. Leka , Katharine K. Reeves , K. E. Korreck , L. Golub , E. E. DeLuca

We use the TESIS EUV telescope to study the current sheet signatures observed during flux rope eruption. The special feature of the TESIS telescope was its ability to image the solar corona up to a distance of 2 $R_\odot$ from the Sun's…

Solar and Stellar Astrophysics · Physics 2016-11-15 Anton Reva , Artem Ulyanov , Ssergey Kuzin

The Ultraviolet Coronagraph Spectrometer (UVCS) observed Doppler shifted material of a partial Halo Coronal Mass Ejection (CME) on December 13 2001. The observed ratio of [O V]/O V] is a reliable density diagnostic important for assessing…

Astrophysics · Physics 2011-02-11 J. -Y. Lee , J. C. Raymond , Y. -K. Ko , K. -S. Kim

Determining the preferred spatial location of the energy input to solar coronal loops would be an important step forward towards a more complete understanding of the coronal heating problem. Following on from Sarkar & Walsh (2008) this…

Solar and Stellar Astrophysics · Physics 2009-07-22 Aveek Sarkar , Robert W Walsh

The eruption of the filament with the kink fashion is often regarded as a signature of the kink instability. However, the kink instability threshold for the filament magnetic structure has been not widely understood. Using the H-alpha…

Solar and Stellar Astrophysics · Physics 2015-05-27 Yi Bi , Yunchun Jiang , Jiayan Yang , Yongyuan Xiang , Yunfang Cai , Weiwei Liu

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

We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \Alfven (fast MHD) waves…

Astrophysics · Physics 2009-11-10 Takeru K. Suzuki

Hot channels (HCs), high temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to make definitive proof given the…

Solar and Stellar Astrophysics · Physics 2015-08-06 Hongqiang Song , Yao Chen , Jie Zhang , Xin Cheng , Bing Wang , Qiang Hu , Gang Li , Yuming Wang

Many models for coronal loops have difficulty explaining the observed EUV brightness of the transition region, which is often significantly less than theoretical models predict. This discrepancy has been addressed by a variety of approaches…

Solar and Stellar Astrophysics · Physics 2009-08-24 Bart De Pontieu , Viggo H. Hansteen , Scott W. McIntosh , Spiros Patsourakos

We perform direct numerical simulations of an externally driven two-dimensional magnetohydrodynamic system over extended periods of time to simulate the dynamics of a transverse section of a solar coronal loop. A stationary and large-scale…

Astrophysics · Physics 2009-10-30 Pablo Dmitruk , Daniel O. Gomez

We present the application of the data-driven branch of the MURaM code, which follows the evolution of the active region 11640 over 4 days starting from 2012 December 30 at 12:00 UT and reproduces many key coronal extreme-ultraviolet (EUV)…

Solar and Stellar Astrophysics · Physics 2026-05-14 Feng Chen

The energy that heats the magnetically closed solar corona originates in the complex motions of the massive photosphere. Turbulent photospheric convection slowly displaces the footpoints of coronal field lines, causing them to become…

In this paper we further develop a model for the heating of coronal loops by Alfven wave turbulence (AWT). The Alfven waves are assumed to be launched from a collection of kilogauss flux tubes in the photosphere at the two ends of the loop.…

Solar and Stellar Astrophysics · Physics 2017-11-08 Adriaan A. van Ballegooijen , Mahboubeh Asgari-Targhi , Alexander Voss

A survey of 28 stars using EUV spectra has been conducted to establish the structure of stellar coronae in active binary systems from the EMD, electron densities, and scale sizes. Observations obtained by the EUVE during 9 years of…

Astrophysics · Physics 2009-11-07 J. Sanz-Forcada , N. S. Brickhouse , A. K. Dupree

We present numerical studies of the nonlinear, resistive magnetohydrodynamic (MHD) evolution of coronal loops. For these simulations we assume that the loops carry no net current, as might be expected if the loop had evolved due to vortex…

Astrophysics · Physics 2009-10-31 T. D. Arber , A. W. Longbottom , R. A. M. Van der Linden
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