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Quasi-constant heating at the footpoints of loops leads to evaporation and condensation cycles of the plasma: thermal non-equilibrium (TNE). This phenomenon is believed to play a role in the formation of prominences and coronal rain.…

Solar and Stellar Astrophysics · Physics 2015-08-27 Clara Froment , Frédéric Auchère , Karine Bocchialini , Eric Buchlin , Chloé Guennou , Jacques Solomon

Here, we study the temperature structure of flaring and non-flaring coronal loops, using extracted loops from images taken in six extreme ultraviolet (EUV) channels recorded by Atmospheric Imaging Assembly (AIA)/ Solar Dynamic Observatory…

Solar and Stellar Astrophysics · Physics 2022-03-14 Narges Fathalian , Seyedeh Somayeh Hosseini Rad , Nasibeh Alipour , Hossein Safari

A well known behavior of EUV light curves of discrete coronal loops is that the peak intensities of cooler channels or spectral lines are reached at progressively later times than hotter channels. This time lag is understood to be the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Nicholeen M. Viall , James A. Klimchuk , NASA Goddard Space Flight Center

The properties of solar flare plasma can be determined from the observation of optically thin lines. The emitting ion distribution determines the shape of the line, with an isothermal Maxwellian ion distribution producing a Gaussian…

Solar and Stellar Astrophysics · Physics 2016-05-25 Natasha Jeffrey , Lyndsay Fletcher , Nicolas Labrosse

We present a first systematic study on the cross-sectional temperature structure of coronal loops using the six coronal temperature filters of the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO). We…

Solar and Stellar Astrophysics · Physics 2015-05-27 Markus J. Aschwanden , Paul Boerner

We report on the plasma properties of small-scale transient events identified in the quiet Sun, coronal holes and their boundaries. We use spectroscopic co-observations from SUMER/SoHO and EIS/Hinode combined with high cadence imaging data…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. S. Madjarska , Z. Huang , J. G. Doyle , S. Subramanian

Plasma composition measurements are a vital tool for the success of current and future solar missions, but density and temperature insensitive spectroscopic diagnostic ratios are sparse, and their underlying accuracy in determining the…

Solar and Stellar Astrophysics · Physics 2024-10-22 David H. Brooks , Harry P. Warren , Deborah Baker , Sarah A. Matthews , Stephanie L. Yardley

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

We present a multi-wavelength analysis of two flare-related jets on November 13, 2014, using data from SDO/AIA, RHESSI, Hinode/XRT, and IRIS. Unlike most coronal jets where hard X-ray (HXR) emissions are usually observed near the jet base,…

Solar and Stellar Astrophysics · Physics 2022-07-13 Yixian Zhang , Sophie Musset , Lindsay Glesener , Navdeep Panesar , Gregory Fleishman

We investigate thermal instability in an electron-ion magnetized plasma relevant to galaxy clusters, solar corona, and other two-component astrophysical objects. We apply the multicomponent plasma approach when the dynamics of all the…

Astrophysics of Galaxies · Physics 2015-05-30 Anatoly K. Nekrasov

Aims: To understand the contribution of active region and flare plasmas to the $\lambda$195 channels of SOHO/EIT (Extreme-ultraviolet Imaging Telescope) and TRACE (Transition Region and Coronal Explorer). Methods: We have analysed an M8…

Astrophysics · Physics 2009-06-25 D. Tripathi , G. Del Zanna , H. E. Mason , C. Chifor

Observations of transition region emission in solar active regions represent a powerful tool for determining the properties of hot coronal loops. In this Letter we present the analysis of new observations of active region moss taken with…

It has previously been argued that 1. spicules do not provide enough pre-heated plasma to fill the corona, and 2. even if they did, additional heating would be required to keep the plasma hot as it expands upward. We here address the…

Solar and Stellar Astrophysics · Physics 2015-06-17 Durgesh Tripathi , James A. Klimchuk

From Doppler velocity maps of active regions constructed from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km/s) that can persist for at least a…

Astrophysics · Physics 2009-11-13 G. A. Doschek , H. P. Warren , J. T. Mariska , K. Muglach , J. L. Culhane , H. Hara , T Watanabe

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

One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often…

Solar and Stellar Astrophysics · Physics 2015-06-12 Harry P. Warren , John T. Mariska , George A. Doschek

We present a model for the intensity of optically thin EUV emission for a plasma atmosphere. We apply our model to the solar corona as observed using the six optically thin EUV channels of the SDO/AIA instrument. The emissivity of the…

Solar and Stellar Astrophysics · Physics 2020-03-31 D. J. Pascoe , A. Smyrli , T. Van Doorsselaere

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

The large uncertainties associated with measuring the amount of high temperature emission in solar active regions represents a significant impediment to making progress on the coronal heating problem. Most current observations at…

Solar and Stellar Astrophysics · Physics 2012-07-20 Luca Teriaca , Harry Warren , Werner Curdt

Investigate particle acceleration and heating in a solar microflare. In a microflare with non-thermal emission to remarkably high energies ($>50$ keV), we investigate the hard X-rays with RHESSI imaging and spectroscopy and the resulting…

Astrophysics · Physics 2010-09-17 I. G. Hannah , S. Krucker , H. S. Hudson , S. Christe , R. P. Lin
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