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Related papers: Further Evidence for Looplike Fine Structure insid…

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Recent high-resolution solar observations have unveiled the presence of small-scale loop-like structures in the lower solar atmosphere, often referred to as unresolved fine structures, low-lying loops, and miniature hot loops. These…

Solar and Stellar Astrophysics · Physics 2025-03-14 Annu Bura , Tanmoy Samanta , Alphonse Sterling , Yajie Chen , Jayant Joshi , Vasyl Yurchyshyn , Ronald L. Moore

The second Hi-C flight (Hi-C2.1) provided unprecedentedly-high spatial and temporal resolution ($\sim$250km, 4.4s) coronal EUV images of Fe IX/X emission at 172 \AA, of AR 12712 on 29-May-2018, during 18:56:21-19:01:56 UT. Three…

We used magnetograms acquired with the {\it Helioseismic and Magnetic Imager} (HMI) on board the {\it Solar Dynamics Observatory} (SDO) to calculate and analyze spatial correlation functions and the multi-fractal spectra in solar active…

Solar and Stellar Astrophysics · Physics 2024-04-11 Valentina Abramenko , Regina Suleymanova

We measure the horizontal subsurface flow in a fast emerging active region (NOAA 11158) using the ring-diagram technique and the HMI high-spatial resolution Dopplergrams. This active region had a complex magnetic structure and displayed…

Solar and Stellar Astrophysics · Physics 2015-08-04 Kiran Jain , S. C. Tripathy , F. Hill

Observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s-1 at temperatures often exceeding a million degree in…

Solar and Stellar Astrophysics · Physics 2011-07-27 Hui Tian , Scott W. McIntosh , Shadia Rifal Habbal , Jiansen He

Coronal plumes are narrow, collimated structures that are primarily viewed above the solar poles and in coronal holes in the extreme ultraviolet, but also in sunspots. Open questions remain about plume formation, including the role of…

Solar and Stellar Astrophysics · Physics 2025-07-24 Ayla Weitz , Sanjiv K. Tiwari , Gianna Cauzzi , Kevin P. Reardon , Bart De Pontieu

We analyze the magnetic evolution of solar active region (AR) NOAA 11476 that, between 9 and 10 May 2012, produced a series of surge-type eruptions accompanied by GOES X-ray class M flares. Using force-free models of the AR coronal…

Solar and Stellar Astrophysics · Physics 2024-04-17 Marcelo López Fuentes , Mariano Poisson , Cristina H. Mandrini

Radio-bright regions near the solar poles are frequently observed in Nobeyama Radioheliograph (NoRH) maps at 17 GHz, and often in association with coronal holes. However, the origin of these polar brightening has not been established yet.…

I report on observations of a set of magnetic loops above a region with late-phase flux emergence taken by IRIS, Hinode and SDO. The loop system consists of many transition region loop threads with size of 5--12\arcsec\ in length and…

Solar and Stellar Astrophysics · Physics 2019-01-09 Zhenghua Huang

Small bipolar magnetic features are observed to appear in the interior of individual granules in the quiet Sun, signaling the emergence of tiny magnetic loops from the solar interior. We study the origin of those features as part of the…

Solar and Stellar Astrophysics · Physics 2018-06-05 F. Moreno-Insertis , J. Martinez-Sykora , V. H. Hansteen , D. Muñoz

We present results of a study of intermittency and multifractality of magnetic structures in solar active regions (ARs). Line-of-sight magnetograms for 214 ARs of different flare productivity observed at the center of the solar disk from…

Solar and Stellar Astrophysics · Physics 2010-12-08 Valentyna Abramenko , Vasyl Yurchyshyn

Solar activity is controlled by the magnetic field, which also causes the variability of the solar irradiance that in turn is thought to influence the climate on Earth. The magnetic field manifests itself in the form of structures of…

Solar and Stellar Astrophysics · Physics 2013-07-10 T. L. Riethmüller

Using spectra obtained by the EIS instrument onboard Hinode, we present a detailed spatially resolved abundance map of an active region (AR)-coronal hole (CH) complex that covers an area of 359 arcsec x 485 arcsec. The abundance map…

Solar and Stellar Astrophysics · Physics 2015-06-17 D. Baker , D. H. Brooks , P. Demoulin , L. van Driel-Gesztelyi , L. M. Green , K. Steed , J. Carlyle

A large part of the hot corona consists of magnetically confined, bright plasma loops. These observed loops are in turn structured into bright strands. We investigate the relationship between magnetic field geometry, plasma properties and…

Solar and Stellar Astrophysics · Physics 2025-12-22 C. A. Breu , D. I. Pontin , E. Priest , I. De Moortel

Solar microflares are ubiquitous in the solar corona, yet their driving mechanisms remain a subject of ongoing debate. Using high-resolution coronal observations from the Solar Orbiter's Extreme Ultraviolet Imager (EUI), we identified about…

Solar and Stellar Astrophysics · Physics 2025-03-17 Qingmei Wang , Yi Bi , Hongfei Liang , Jiayan Yang , Liufan Gong

We report one of several homologous non-radial eruptions from NOAA active region (AR) 11158 that are strongly modulated by the local magnetic field as observed with the Solar Dynamic Observatory (SDO). A small bipole emerged in the sunspot…

Solar and Stellar Astrophysics · Physics 2015-06-11 Xudong Sun , Todd Hoeksema , Yang Liu , Qingrong Chen , Keiji Hayashi

Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the…

Solar and Stellar Astrophysics · Physics 2015-10-07 Shin Toriumi , Yukio Katsukawa , Mark C. M. Cheung

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed…

Solar and Stellar Astrophysics · Physics 2015-11-04 X. Fang , D. Yuan , T. Van Doorsselaere , R. Keppens , C. Xia

Vortex-flows exist across a broad range of spatial and temporal scales in the solar atmosphere. Small-scale vortices have been proposed to play an important role in energy transport in the solar atmosphere. However, their physical…

Solar and Stellar Astrophysics · Physics 2021-01-04 Nitin Yadav , Robert H. Cameron , Sami K. Solanki

Using high spatial and temporal data from the \emph{Solar Dynamics Observatory} (\emph{SDO}) and the \emph{Interface Region Imaging Spectrograph} (\emph{IRIS}), several observational signatures of magnetic reconnection in the course of…

Solar and Stellar Astrophysics · Physics 2018-07-25 Bo Yang , Jiayan Yang , Yi Bi , Junchao Hong , Haidong Li , Zhe Xu , Hechao Chen