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Related papers: Hot coronal loops associated with umbral brighteni…

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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

Understanding the relationship between the magnetic field and coronal heating is one of the central problems of solar physics. However, studies of the magnetic properties of impulsively heated loops have been rare. We present results from a…

Solar and Stellar Astrophysics · Physics 2019-06-12 Ignacio Ugarte-Urra , Nicholas A. Crump , Harry P. Warren , Thomas Wiegelmann

We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in EUV images. The UV 1600 \AA emission…

Solar and Stellar Astrophysics · Physics 2015-06-11 Y. Li , J. Qiu , M. D. Ding

A recent analysis has suggested that the heating of plasma loops in the solar corona depends not just on the Poynting flux but also on processes yet to be identified. This discovery reflects and refines earlier questions such as, why and…

Solar and Stellar Astrophysics · Physics 2024-08-16 P. G. Judge , N. P. M. Kuin

We derived the coronal magnetic field, plasma density, and temperature from the observation of polarization and intensity of radio thermal free-free emission using the Nobeyama Radioheliograph (NoRH) and extreme ultraviolet (EUV)…

Context. The solar corona maintains temperatures of a million Kelvin or more. The plasma heating mechanisms responsible for these extreme temperatures are still unclear. Large regions of magnetic activity in the photosphere cause extreme…

Solar and Stellar Astrophysics · Physics 2025-03-17 I. Kraus , Ph. -A. Bourdin , J. Zender , M. Bergmann , A. Hanslmeier

Context: Long-period intensity pulsations were recently detected in the EUV emission of coronal loops, and have been attributed to cycles of plasma evaporation and condensation driven by thermal non-equilibrium (TNE). Numerical simulations…

Solar and Stellar Astrophysics · Physics 2020-02-12 Gabriel Pelouze , Frédéric Auchère , Karine Bocchialini , Clara Froment , Susanna Parenti , Elie Soubrié

We analyzed a coronal loop observed with the Normal Incidence Spectrometer (NIS), which is part of the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO). The measured Doppler shifts and proper…

Astrophysics · Physics 2009-11-10 C. Gontikakis , G. J. D. Petrie , H. C. Dara , K. Tsinganos

We present observations of high temperature emission in the core of a solar active region using instruments on Hinode and SDO. These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Harry P. Warren , David H. Brooks , Amy R. Winebarger

Evidence for small amounts of very hot plasma has been found in active regions and might be the indication of an impulsive heating, released at spatial scales smaller than the cross section of a single loop. We investigate the heating and…

Solar and Stellar Astrophysics · Physics 2016-01-13 E. Tajfirouze , F. Reale , A. Petralia , P. Testa

One scenario proposed to explain the million degrees solar corona is a finely-stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor…

Solar and Stellar Astrophysics · Physics 2015-05-28 Fabio Reale , Massimiliano Guarrasi , Paola Testa , Edward E. DeLuca , Giovanni Peres , Leon Golub

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

Twisted magnetic fields should be ubiquitous in flare-producing active regions where the magnetic fields are strongly non-potential. It has been shown that reconnection in helical magnetic coronal loops results in plasma heating and…

Solar and Stellar Astrophysics · Physics 2016-01-20 R. F. Pinto , M. Gordovskyy , P. K. Browning , N. Vilmer

In previous studies a very hot plasma component has been diagnosed in solar active regions through the images in three different narrow-band channels of SDO/AIA. This diagnostic from EUV imaging data has also been supported by the matching…

Solar and Stellar Astrophysics · Physics 2015-06-18 A. Petralia , F. Reale , P. Testa , G. Del Zanna

Relaxation of braided coronal magnetic fields through reconnection is thought to be a source of energy to heat plasma in active region coronal loops. However, observations of active region coronal heating associated with an untangling of…

Spicules have been proposed as significant contributors to the mass and energy balance of the corona. While previous observations have provided a glimpse of short-lived transient brightenings in the corona that are associated with spicules,…

Solar and Stellar Astrophysics · Physics 2017-10-19 Bart De Pontieu , Ineke De Moortel , Juan Martinez-Sykora , Scott McIntosh

The corona of the Sun is dominated by emission from loop-like structures. When observed in X-ray or extreme ultraviolet emission, these million K hot coronal loops show a more or less constant cross section. In this study we show how the…

Solar and Stellar Astrophysics · Physics 2015-06-11 H. Peter , S. Bingert

Coronal loops are plasma structures in the solar atmosphere with temperatures reaching millions of Kelvin, shaped and sustained by the magnetic field. However, their morphology and fundamental nature remain subjects of debate. By studying…

Solar and Stellar Astrophysics · Physics 2026-01-14 N. Vasantharaju , H. Peter , L. P. Chitta , S. Mandal

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

We perform MHD modeling of a single bright coronal loop to include the interaction with a non-uniform magnetic field. The field is stressed by random footpoint rotation in the central region and its energy is dissipated into heating by…

Solar and Stellar Astrophysics · Physics 2016-10-12 F. Reale , S. Orlando , M. Guarrasi , A. Mignone , G. Peres , A. W. Hood , E. R. Priest