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Related papers: On Thermal-Pulse-Driven Plasma Flows in Coronal Fu…

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We investigate the thermal, kinematic and magnetic structure of small-scale heating events in an emerging flux region (EFR). We use high-resolution multi-line observations (including Ca II 8542~\AA, Ca II K, and Fe I 6301~\AA line pair) of…

Solar and Stellar Astrophysics · Physics 2023-09-14 Rahul Yadav , Maria D. Kazachenko , Andrey N. Afanasyev , Jaime de la Cruz Rodríguez , Jorrit Leenaarts

Recent studies show that active-region (AR) upflowing plasma, observed by the EUV-Imaging Spectrometer (EIS), onboard Hinode, can gain access to open field-lines and be released into the solar wind (SW) via magnetic-interchange reconnection…

Solar and Stellar Astrophysics · Physics 2015-06-23 C. H. Mandrini , F. A. Nuevo , A. M. Vásquez , P. Démoulin , L. van Driel-Gesztelyi , D. Baker , J. L. Culhane , G. D. Cristiani , M. Pick

We present numerical models from the field-aligned Hydrodynamics and Radiation Code (HYDRAD) of a highly asymmetric closed coronal loop with near-singular expansion factor. This loop was chosen to simulate a coronal magnetic flux tube that…

Solar and Stellar Astrophysics · Physics 2023-02-08 Emily I Mason , Spiro K Antiochos , Stephen Bradshaw

Magnetic reconnection is the key mechanism for energy release in solar eruptions, where the high-temperature emission is the primary diagnostic for investigating the plasma properties during the reconnection process. Non-thermal broadening…

Solar and Stellar Astrophysics · Physics 2022-11-15 Chengcai Shen , Vanessa Polito , Katharine K. Reeves , Bin Chen , Sijie Yu , Xiaoyan Xie

The origin of solar transition region redshifts is not completely understood. Current research is addressing this issue by investigating three-dimensional magneto-hydrodynamic models that extend from the photosphere to the corona. By…

Solar and Stellar Astrophysics · Physics 2015-05-28 Pia Zacharias , Sven Bingert , Hardi Peter

We show that the coronal heating and the acceleration of the fast solar wind in the coronal holes are natural consequence of the footpoint fluctuations of the magnetic fields at the photosphere by one-dimensional, time-dependent, and…

Astrophysics · Physics 2007-05-23 Takeru K. Suzuki , Shu-ichiro Inutsuka

Persistent plasma upflows were observed with Hinode's EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR,…

We analyzed AIA/SDO high-cadence images in all bands, HMI/SDO data, soft X-ray images from SXI/GOES-15, and Halpha images from the GONG network. We detected umbral brightenings that were visible in all AIA bands as well as in Halpha.…

Solar and Stellar Astrophysics · Physics 2015-06-16 C. E. Alissandrakis , S. Patsourakos

A hot corona is suggested to be above the standard thin disk. The anisotropy of hard X-ray emission in radio-quiet active galactic nuclei implies that the corona is not static and probably moves outwards like winds. We perform…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Xiao-Hong Yang , De-Fu Bu , Qi-Xiu Li

As one of the most spectacular energy release events in the solar system, solar flares are generally powered by magnetic reconnection in the solar corona. As a result of the re-arrangement of magnetic field topology after the reconnection…

Solar and Stellar Astrophysics · Physics 2021-03-29 Tanmoy Samanta , Hui Tian , Bin Chen , Katharine K. Reeves , Mark C. M. Cheung , Angelos Vourlidas , Dipankar Banerjee

Recent observations from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode have shown that low density areas on the periphery of active regions are characterized by strong blue-shifts at 1 MK. These Doppler shifts have been…

Solar and Stellar Astrophysics · Physics 2015-05-19 Ignacio Ugarte-Urra , Harry P. Warren

Recent observations of coronal hole areas with the XRT and EIS instruments onboard the Hinode satellite have shown with unprecedented detail the launching of fast, hot jets away from the solar surface. In some cases these events coincide…

Astrophysics · Physics 2009-11-13 F. Moreno-Insertis , K. Galsgaard , I. Ugarte-Urra

One of the key processes associated with the "standard" flare model is chromospheric evaporation, a process where plasma heated to high temperatures by energy deposition at the flare footpoints is driven upwards into the corona. Despite…

Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which…

We use coronal imaging observations with SDO/AIA, and Hinode/EIS spectral data, to explore the potential of narrow band EUV imaging data for diagnosing the presence of hot (T >~5MK) coronal plasma in active regions. We analyze observations…

Solar and Stellar Astrophysics · Physics 2015-06-04 Paola Testa , Fabio Reale

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

The excess broadening of high-temperature spectral lines, long observed near the tops of flare arcades, is widely considered to result from magnetohydrodynamic (MHD) turbulence. According to different theories, plasma turbulence is also…

Solar and Stellar Astrophysics · Physics 2024-07-18 William Ashfield , Vanessa Polito , Sijie Yu , Hannah Collier , Laura Hayes

There is evidence for coronal plasma flows to break down into fragments and to be laminar. We investigate this effect by modeling flows confined along magnetic channels. We consider a full MHD model of a solar atmosphere box with a dipole…

Solar and Stellar Astrophysics · Physics 2017-12-27 A. Petralia , F. Reale , P. Testa

Observation of coronal EUV spectral lines sensitive to different temperatures offers an opportunity to evaluate the thermal structure and flows in flaring atmospheres. This can be used to estimate the partitioning between the thermal and…

Solar and Stellar Astrophysics · Physics 2016-04-27 Mykola Gordovskyy , Eduard Kontar , Philippa Browning

A significant impediment to solving the coronal heating problem is that we currently only observe active region (AR) loops in their cooling phase. Previous studies showed that the evolution of cooling loop densities and apex temperatures…

Solar and Stellar Astrophysics · Physics 2024-01-10 David H. Brooks , Jeffrey W. Reep , Ignacio Ugarte-Urra , John E. Unverferth , Harry P. Warren