English
Related papers

Related papers: Active region upflows in various coronal structure…

200 papers

Solar sub-surface fluid topology provides an indirect approach to examine the internal characteristics of active regions (ARs). Earlier studies have revealed the prevalence of strong flows in the interior of ARs having complex magnetic…

Solar and Stellar Astrophysics · Physics 2010-04-19 R. A. Maurya , A. Ambastha

The extreme space weather conditions resulting from high energetic events likes solar flares and Coronal Mass Ejections (CMEs) demand for reliable space weather forecasting. The magnetic flux tubes while rising through the convection zone…

Solar and Stellar Astrophysics · Physics 2022-10-19 B Lekshmi , Kiran Jain , Rudolf W. Komm , Dibyendu Nandy

In order to better understand the nature of active region outflows, the electron density was measured by using a density-sensitive line pair Fe xiv 264.78A/274.20A.Since coronal line profiles of the outflow region are composed of a major…

Solar and Stellar Astrophysics · Physics 2015-06-03 Naomasa Kitagawa , Takaaki Yokoyama

Emerging active regions are associated with convective flows on the spatial scale and lifetimes of supergranules. To understand how these flows are involved in the formation of active regions, we aim to identify where active regions emerge…

Solar and Stellar Astrophysics · Physics 2024-07-17 Hannah Schunker , William Roland-Batty , Aaron C. Birch , Douglas C. Braun , Robert H. Cameron , L. Gizon

Magnetic fields in the solar corona are responsible for a wide range of phenomena. However, any direct measurements of the coronal magnetic fields are very difficult due to lack of suitable spectral lines, weak magnetic fields, and high…

Solar and Stellar Astrophysics · Physics 2013-10-28 P. Vemareddy , A. Ambastha , T. Wiegelmann

The chromosphere above active regions (ARs) on the Sun hosts magnetized supersonic downflows. Studies of these supersonic downflows help to decipher the magnetic fine structure and dynamics of the chromosphere. We perform a statistical…

Solar and Stellar Astrophysics · Physics 2022-07-26 K. Sowmya , A. Lagg , S. K. Solanki , J. S. Castellanos Durán

The relationships among coronal loop structures at different temperatures is not settled. Previous studies have suggested that coronal loops in the core of an active region are not seen cooling through lower temperatures and therefore are…

Solar and Stellar Astrophysics · Physics 2011-02-11 Ignacio Ugarte-Urra , Harry P. Warren , David H. Brooks

Context. Supra-arcade downflows (SADs) have been frequently observed during the gradual phase of solar flares near the limb. In coronal emission lines sensitive to flaring plasmas, they appear as tadpole-like dark voids against the diffuse…

Solar and Stellar Astrophysics · Physics 2017-10-18 Xin Chen , Rui Liu , Na Deng , Haimin Wang

In this study we report detailed observations of magnetic environment at four footpoints of two warm coronal loops observed on 5 May 2016 in NOAA AR 12542 (Loop I) and 17 Dec 2015 in NOAA AR 12470 (Loop II). These loops were connecting a…

Solar and Stellar Astrophysics · Physics 2019-03-29 Seray Şahin , Vasyl Yurchyshyn , Pankaj Kumar , Ali Kilcik , Kwangsu Ahn , Xu Yang

We present results of a multi-wavelength study of episodic plasma injection into the corona of AR 10942. We exploit long-exposure images of the Hinode and Transition Region and Coronal Explorer (TRACE) spacecraft to study the properties of…

Solar and Stellar Astrophysics · Physics 2014-11-20 Scott W. McIntosh , Bart De Pontieu

Magnetic active regions on the Sun are harbingers of space weather events. Understanding the physics of how they form and evolve will improve space weather forecasting. Our aim is to characterise the surface magnetic field and flows for a…

Solar and Stellar Astrophysics · Physics 2023-12-08 Camron S. Alley , Hannah Schunker

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

Earlier studies using extreme-ultraviolet images and line-of-sight magnetograms from the Solar Dynamics Observatory (SDO) have suggested that active region (AR) plages and strong network concentrations often have small, looplike features…

Solar and Stellar Astrophysics · Physics 2021-04-15 Y. -M. Wang , I. Ugarte-Urra , J. W. Reep

Strong solar flares and coronal mass ejections, here defined not only as the bursts of electromagnetic radiation but as the entire process in which magnetic energy is released through magnetic reconnection and plasma instability, emanate…

Solar and Stellar Astrophysics · Physics 2019-05-29 Shin Toriumi , Haimin Wang

The dynamics of horizontal plasma flows during the first hours of the emergence of active region magnetic flux in the solar photosphere have been analyzed using SOHO/MDI data. Four active regions emerging near the solar limb have been…

Solar and Stellar Astrophysics · Physics 2017-05-01 A. Khlystova

We study the effect of newly emerged solar active regions (ARs) on the large-scale magnetic environment of pre-existing ARs (PEARs). We first present a theoretical approach to quantify the "interaction energy" between new ARs and PEARs as…

Solar and Stellar Astrophysics · Physics 2016-06-09 Yixing Fu , Brian T. Welsch

Quasi-periodic intensity disturbances propagating upward along the coronal structure have been extensively studied using EUV imaging observations from SOHO/EIT and TRACE. They were interpreted as either slow mode magnetoacoustic waves or…

Solar and Stellar Astrophysics · Physics 2012-01-26 Tongjiang Wang , Leon Ofman , Joseph M. Davila

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

Emerging dimming occurs in isolated solar active regions (ARs) during the early stages of magnetic flux emergence. Observed by the Atmospheric Imaging Assembly, it features a rapid decrease in extreme-ultraviolet (EUV) emission in the 171…

Solar and Stellar Astrophysics · Physics 2021-05-05 Anna V. Payne , Xudong Sun

Both coronal holes and active regions are source regions of the solar wind. The distribution of these coronal structures across both space and time is well known, but it is unclear how much each source contributes to the solar wind. In this…

Solar and Stellar Astrophysics · Physics 2021-08-11 D. Stansby , L. M. Green , L. van Driel-Gesztelyi , T. S. Horbury