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One proposed resolution to the long-standing problem of solar coronal heating involves the buildup of magnetic energy in the corona due to turbulent motions at the photosphere that braid the coronal field, and the subsequent release of this…

Solar and Stellar Astrophysics · Physics 2015-05-27 D. I. Pontin , G. Hornig

We detect and analyse transverse oscillations in a coronal loop, lying at the south east limb of the Sun as seen from the \textit{{Atmospheric Imaging Assembly}} (AIA) onboard \textit{{Solar Dynamics Observatory}} (SDO). The jet is believed…

Solar and Stellar Astrophysics · Physics 2016-12-07 S. Sarkar , V. Pant , A. K. Srivastava , D. Banerjee

We present high-resolution observations of a magnetic reconnection event in the solar atmosphere taken with the New Vacuum Solar Telescope, AIA and HMI. The reconnection event occurred between the threads of a twisted arch filament system…

Solar and Stellar Astrophysics · Physics 2018-02-14 Zhenghua Huang , Chaozhou Mou , Hui Fu , Linhua Deng , Bo Li , Lidong Xia

Aims. We aim to infer information about the magnetic field in the low solar corona from coronal rain clumps using high-resolution spectropolarimetric observations in the Ca ii 8542 A line obtained with the Swedish 1-m Solar Telescope.…

Solar and Stellar Astrophysics · Physics 2021-06-09 M. Kriginsky , R. Oliver , P. Antolin , D. Kuridze , N. Freij

We report on the variability of rotation periods of solar coronal layers with respect to temperature (or, height). For this purpose, we have used the observations from Atmospheric Imaging Assembly (AIA) telescope on board Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2020-02-19 Jaidev Sharma , Brajesh Kumar , Anil K. Malik , Hari Om Vats

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 thermal structure of a coronal loop, both along and across the loop, is vital in determining the exact plasma heating mechanism. High resolution spectroscopic observations of the off-limb corona were made using 25 cm Norikura…

Solar and Stellar Astrophysics · Physics 2015-06-15 S. Krishna Prasad , Jagdev Singh , K. Ichimoto

Aims. We construct a new analytical model of a solar coronal loop that is embedded in a gravitationally stratified and magnetically confined atmosphere. On the basis of this analytical model, we devise a numerical model of solar coronal…

Solar and Stellar Astrophysics · Physics 2015-03-25 K. Murawski , A. Solov'ev , J. Kraskiewicz , A. K. Srivastava

Magnetic loops are building blocks of the closed-field corona. While active region loops are readily seen in images taken at EUV and X-ray wavelengths, quiet Sun loops are seldom identifiable and therefore difficult to study on an…

Solar and Stellar Astrophysics · Physics 2015-06-05 Zhenguang Huang , Richard A. Frazin , Enrico Landi , Ward B. Manchester , Alberto M. Vásquez , Tamas I. Gombosi

Coronal loops serve as the fundamental building blocks of the solar corona. Therefore, comprehending their properties is essential in unraveling the dynamics of the Sun's upper atmosphere. In this study, we conduct a comparative analysis of…

We re-analyse spectropolarimetric data of AB Dor taken in 1996 December using a surface imaging code that can model the magnetic field of the star as a non-potential current-carrying magnetic field. We find that a non-potential field needs…

Astrophysics · Physics 2009-11-07 G. A. J. Hussain , A. A. van Ballegooijen , M. Jardine , A. Col lier Cameron

Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Recent hydrodynamical models attempt an investigation by placing swarms of 'nanoflares' at random sites and times in modeled…

Solar and Stellar Astrophysics · Physics 2016-11-30 K. Moraitis , A. Toutountzi , H. Isliker , M. Georgoulis , L. Vlahos , G. Chintzoglou

The solar atmosphere shows anomalous variation in temperature, starting from the 5500 K photosphere to the million-degree Kelvin corona. The corona itself expands into the interstellar medium as the free streaming solar wind, which…

Solar and Stellar Astrophysics · Physics 2023-04-05 Vishal Upendran

Recent radioastronomical observations of Faraday rotation in the solar corona can be interpreted as evidence for coronal currents, with values as large as $2.5 \times 10^9$ Amperes (Spangler 2007). These estimates of currents are used to…

Astrophysics · Physics 2020-01-29 Steven R. Spangler

Solar flares are one of the main forces behind space weather events. However the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Imada , K. Aoki , H. Hara , T. Watanabe , L. K. Harra , T. Shimizu

Magnetic fields in the sun's outer atmosphere -- the corona -- control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly…

What physical mechanisms heat the outer solar or stellar atmosphere to million-Kelvin temperatures is a fundamental but long-standing open question. In particular, the solar corona in active region cores contains an even hotter component…

Solar and Stellar Astrophysics · Physics 2024-04-09 Zekun Lu , Feng Chen , M. D. Ding , Can Wang , Yu Dai , Xin Cheng

We study a series of relations between physical parameters in coronal loops of the quiet Sun reconstructed by combining tomographic techniques and modeling of the coronal magnetic field. We use differential emission measure tomography…

Solar and Stellar Astrophysics · Physics 2022-06-22 C. Mac Cormack , M. López Fuentes , C. H. Mandrini , D. G. Lloveras , M. Poisson , A. M. Vásquez

Coronal fan loops rooted in sunspot umbra show outward propagating waves with subsonic phase speed and period around 3-min. However, their source region in the lower atmosphere is still ambiguous. We performed multi-wavelength observations…

Solar and Stellar Astrophysics · Physics 2023-09-06 Ananya Rawat , Girjesh Gupta

We examine the hypothesis that ``cool loops'' dominate emission from solar transition region plasma below temperatures of $2\times10^5$K. We compare published VAULT images of H L$\alpha$, a lower transition region line, with…

Astrophysics · Physics 2009-11-13 Philip G. Judge , Rebecca Centeno
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