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Related papers: Cool transition region loops observed by the Inter…

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Loops are one of the fundamental structures that trace the geometry of the magnetic field in the solar atmosphere. Their evolution and dynamics provide a crucial proxy for studying how the magnetized structures are formed and heated in the…

Solar and Stellar Astrophysics · Physics 2020-01-08 Zhenghua Huang , Bo Li , Lidong Xia , Mijie Shi , Hui Fu , Zhenyong Hou

Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity. Aims. We use observations with the new Interface Region…

Solar and Stellar Astrophysics · Physics 2014-10-29 Leping Li , Hardi Peter , Feng Chen , Jun Zhang

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

The Interface Region Imaging Spectrograph (IRIS) has observed bright spots at the transition region footpoints associated with heating in the overlying loops, as observed by coronal imagers. Some of these brightenings show significant…

Solar and Stellar Astrophysics · Physics 2019-09-04 Fabio Reale , Paola Testa , Antonino Petralia , David R. Graham

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

We observe plasma flows in cool loops using the Slit-Jaw Imager (SJI) onboard the Interface Region Imaging Spectrometer (IRIS). Huang et al. (2015) observed unusually broadened Si IV 1403 angstrom line profiles at the footpoints of such…

Solar and Stellar Astrophysics · Physics 2020-05-27 A. K. Srivastava , Yamini K. Rao , P. Konkol , K. Murawski , M. Mathioudakis , Sanjiv K. Tiwari , E. Scullion , J. G. Doyle , B. N. Dwivedi

Coronal loops are basic building blocks of solar atmosphere and are observed on various length scales. However, their formation mechanism is still unclear. In this paper, we present the spectroscopic and imaging observations of small-scale…

Solar and Stellar Astrophysics · Physics 2022-04-06 Girjesh R. Gupta , Sushree S. Nayak

We observed quiescent coronal loops using multi-wavelength observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) on 2016 April 13. The flows at the footpoints of such loop systems are studied…

Solar and Stellar Astrophysics · Physics 2019-10-02 Yamini K. Rao , Abhishek K. Srivastava , Pradeep Kayshap , Bhola N. Dwivedi

Nanoflares are regarded as one of the major mechanisms of magnetic energy release and coronal heating in the solar outer atmosphere. We conduct a statistical study on the response of the chromosphere and transition region to nanoflares, as…

Solar and Stellar Astrophysics · Physics 2023-03-29 Kyuhyoun Cho , Paola Testa , Bart De Pontieu , Vanessa Polito

Transition-region explosive events (EEs) are characterized by non-Gaussian line profiles with enhanced wings at Doppler velocities of 50-150 km/s. They are believed to be the signature of solar phenomena that are one of the main…

Solar and Stellar Astrophysics · Physics 2016-11-15 Z. Huang , M. S. Madjarska , E. M. Scullion , L. -D. Xia , J. G. Doyle , T. Ray

Low-lying loops have been discovered at the solar limb in transition region temperatures by the Interface Region Imaging Spectrograph (IRIS). They do not appear to reach coronal temperatures, and it has been suggested that they are the…

Solar and Stellar Astrophysics · Physics 2018-04-11 Tiago M. D. Pereira , Luc Rouppe van der Voort , Viggo H. Hansteen , Bart De Pontieu

The Interface Region Imaging Spectrograph (IRIS) reveals numerous small-scale (sub-arcsecond) brightenings that appear as bright dots sparkling the solar transition region in active regions. Here, we report a statistical study on these…

Solar and Stellar Astrophysics · Physics 2018-03-23 Zhenyong Hou , Zhenghua Huang , Lidong Xia , Bo Li , Maria S. Madjarska , Hui Fu

A comprehensive study of the physical parameters of active region fan loops is presented using the observations recorded with the Interface Region Imaging Spectrometer (IRIS), the EUV Imaging Spectrometer (EIS) on-board Hinode and the…

Solar and Stellar Astrophysics · Physics 2017-02-08 Avyarthana Ghosh , Durgesh Tripathi , G. R. Gupta , Vanessa Polito , Helen E. Mason , Sami K. Solanki

Loops are fundamental structures in the magnetized atmosphere of the sun. Their physical properties are crucial for understanding the nature of the solar atmosphere. Transition region loops are relatively dynamic and their physical…

Solar and Stellar Astrophysics · Physics 2024-04-16 Shiyu Liang , Ziyuan Wang , Zhenghua Huang , Hengyuan Wei , Hui Fu , Ming Xiong , Lidong Xia

We analyzed spectral and imaging data from the Interface Region Imaging Spectrograph (IRIS), images from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO), and magnetograms from the Helioseismic and Magnetic…

Solar and Stellar Astrophysics · Physics 2017-07-12 C. E. Alissandrakis , A. Koukras , S. Patsourakos , A. Nindos

Transition region (TR) loops are arcade-like features in the solar transition region, with temperatures roughly between $2\times10^4$ K and $6\times10^5$ K. They are a fundamental building block of TR, which are results of the coupling…

Solar and Stellar Astrophysics · Physics 2026-05-04 Zhenghua Huang

We observed rapid variability ($\lesssim 60$ s) at the footpoints of transient hot ($\sim 8-10$ MK) coronal loops in active region cores, with the Interface Region Imaging Spectrograph (IRIS). The high spatial ($\sim 0.33$ arcsec) and…

Solar and Stellar Astrophysics · Physics 2020-02-12 Paola Testa , Vanessa Polito , Bart De Pontieu

IRIS data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.33 arcsec. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km/s and…

The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that…

The study examines the heating profile of hot solar transition region loops, particularly focusing on transient brightenings observed in IRIS 1400{\AA} slit-jaw images. The findings challenge the adequacy of simplistic, singular heating…

Solar and Stellar Astrophysics · Physics 2024-05-15 Shah Mohammad Bahauddin , Stephen J Bradshaw
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