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Related papers: Mass Flows in Expanding Coronal Loops

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Very recently, To et al.~have experimentally explored granular flow in a cylindrical silo, with a bottom wall that rotates horizontally with respect to the lateral wall \cite{Kiwing2019}. Here, we numerically reproduce their experimental…

Soft Condensed Matter · Physics 2021-04-30 D. Hernández-Delfin , T. Pongó , K. To , T. Börzsönyi , R. C. Hidalgo

Observational measurements of active region emission measures contain clues to the time-dependence of the underlying heating mechanism. A strongly non-linear scaling of the emission measure with temperature indicates a large amount of hot…

Solar and Stellar Astrophysics · Physics 2015-06-11 Stephen J. Bradshaw , James A. Klimchuk , Jeffrey W. Reep

Upflows at the edges of active regions (ARs) are studied by spatially and temporally combining multi-instrument observations obtained with EIS/Hinode, AIA and HMI/SDO and IBIS/NSO, to derive their plasma parameters. This information is used…

Solar and Stellar Astrophysics · Physics 2015-11-18 K. Vanninathan , M. S. Madjarska , K. Galsgaard , Z. Huang , J. G. Doyle

We explore the suggestions by Uzdensky (2007) and Cassak et al. (2008) that coronal loops heated by magnetic reconnection should self-organize to a state of marginal collisionality. We discuss their model of coronal loop dynamics with a…

Solar and Stellar Astrophysics · Physics 2015-06-05 S. Imada , E. G. Zweibel

The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of…

Solar and Stellar Astrophysics · Physics 2015-05-18 H. Peter

We present a series of numerical simulations of the quiet Sun plasma threaded by magnetic fields that extend from the upper convection zone into the low corona. We discuss an efficient, simplified approximation to the physics of optically…

Solar and Stellar Astrophysics · Physics 2015-05-27 William P. Abbett , George H. Fisher

Magnetohydrodynamic waves are important for diagnosing the physical parameters of coronal plasmas. Field-aligned flows appear frequently in coronal loops.We examine the effects of transverse density and plasma flow structuring on standing…

Solar and Stellar Astrophysics · Physics 2014-09-05 Bo Li , Shao-Xia Chen , Li-Dong Xia , Hui Yu

One of the outstanding problems in all of space science is uncovering how the solar corona is heated to temperatures greater than 1 MK. Though studied for decades, one of the major difficulties in solving this problem has been unraveling…

Solar and Stellar Astrophysics · Physics 2015-06-15 Nicholeen M. Viall , James A. Klimchuk

One of the major discoveries of Hinode's Extreme-ultraviolet Imaging Spectrometer (EIS) is the presence of upflows at the edges of active regions. As active regions are magnetically connected to the large-scale field of the corona, these…

We investigate numerically the surface flow on the secondary star during outbursts. We use a simple model for the irradiation and the geometry of the secondary star: the irradiation temperature is treated as a free parameter and the…

Astrophysics · Physics 2009-11-13 M. Viallet , J. -M. Hameury

Waves play an important role in the heating of solar atmosphere, however, observations of wave propagation and damping from the solar photosphere to corona through chromosphere and transition region are very rare. Recent observations have…

Solar and Stellar Astrophysics · Physics 2024-08-01 Ananya Rawat , Girjesh R. Gupta

Context. The details of the spectral profiles of extreme UV emission lines from solar active regions contain key information to investigate the structure, dynamics, and energetics of the solar upper atmosphere. Aims. We characterize the…

Solar and Stellar Astrophysics · Physics 2019-06-19 Leping Li , Hardi Peter

The outburst cycles of black hole X-ray transients are now generally understood as caused by a thermal instability in the accretion disk, the same mechanism as in dwarf novae outbursts. During quiescence the accretion occurs via a cool disk…

Astrophysics · Physics 2009-11-06 Emmi Meyer-Hofmeister , Friedrich Meyer

In a recent work Grappin et al. [1] have shown that low- frequency movements can be transmitted from one footpoint to the other along a magnetic loop, thus mimicking a friction effect of the corona on the photosphere, and invalidating the…

Solar and Stellar Astrophysics · Physics 2014-11-20 A. Verdini , R. Grappin , M. Velli

The transition region between the Sun's corona and chromosphere is important to the mass and energy transfer from the lower atmosphere to the corona; consequently, this region has been studied intensely with ultraviolet (UV) and extreme…

Solar and Stellar Astrophysics · Physics 2023-02-08 C. Gontikakis , S. K. Antiochos , P. R. Young

We use local stratified shearing-box simulations to elucidate the impact of two-temperature thermodynamics on the thermal structure of coronae in radiatively efficient accretion flows. Rather than treating the coronal plasma as an…

High Energy Astrophysical Phenomena · Physics 2023-11-01 Christopher J. Bambic , Eliot Quataert , Matthew W. Kunz

We present observations of persistent oscillations of some bright features in the upper-chromosphere/transition-region above sunspots taken by IRIS SJ 1400 {\AA} and upward propagating quasi-periodic disturbances along coronal loops rooted…

Solar and Stellar Astrophysics · Physics 2018-03-21 Zhenyong Hou , Zhenghua Huang , Lidong Xia , Bo Li , Hui Fu

The heating of the plasma in the solar atmosphere is discussed within both frameworks of fluid and kinetic drift wave theory. We show that the basic ingredient necessary for the heating is the presence of density gradients in the direction…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. Vranjes , S. Poedts

We study the effects of thermal conduction in a hot, active corona above an accretion disk. We assume that all of the dissipative heating takes place in the corona. We find that the importance of conduction decreases with increases in the…

Astrophysics · Physics 2009-10-30 Andrzej Maciolek-Niedzwiecki , Julian H. Krolik , Andrzej A. Zdziarski

Context. We have conducted a 3D MHD simulation of the solar corona above an active region (AR) in full scale and high resolution, which shows coronal loops, and plasma flows within them, similar to observations. Aims. We want to find the…

Solar and Stellar Astrophysics · Physics 2017-09-19 Philippe-A. Bourdin , Sven Bingert , Hardi Peter