scholarly journals Time Variability of the “Quiet” Sun Observed withTRACE. II. Physical Parameters, Temperature Evolution, and Energetics of Extreme‐Ultraviolet Nanoflares

2000 ◽  
Vol 535 (2) ◽  
pp. 1047-1065 ◽  
Author(s):  
Markus J. Aschwanden ◽  
Ted D. Tarbell ◽  
Richard W. Nightingale ◽  
Carolus J. Schrijver ◽  
Alan Title ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Temperature Evolution ◽  
Time Variability ◽  
Physical Parameters ◽  
Quiet Sun

scholarly journals OBSERVATIONS AND MODELING OF THE EMERGING EXTREME-ULTRAVIOLET LOOPS IN THE QUIET SUN AS SEEN WITH THESOLAR DYNAMICS OBSERVATORY

2013 ◽  
Vol 768 (1) ◽  
pp. 32 ◽  
Author(s):  
L. P. Chitta ◽  
R. Kariyappa ◽  
A. A. van Ballegooijen ◽  
E. E. DeLuca ◽  
S. S. Hasan ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Quiet Sun

Measuring Active and Quiet-Sun Coronal Plasma Properties with Extreme-Ultraviolet Spectra from SERTS

1996 ◽  
Vol 106 ◽  
pp. 143 ◽  
Author(s):  
Jeffrey W. Brosius ◽  
Joseph M. Davila ◽  
Roger J. Thomas ◽  
Brunella C. Monsignori-Fossi
Keyword(s):  
Extreme Ultraviolet ◽  
Coronal Plasma ◽  
Plasma Properties ◽  
Quiet Sun ◽  
Ultraviolet Spectra

scholarly journals Photospheric magnetic topology of a north polar region

2020 ◽  
Vol 635 ◽  
pp. A210 ◽  
Author(s):  
A. Pastor Yabar ◽  
M. J. Martínez González ◽  
M. Collados
Keyword(s):  
Polar Region ◽  
Large Fraction ◽  
Line Of Sight ◽  
Physical Parameters ◽  
Polar Regions ◽  
Quiet Sun ◽  
The North ◽  
Disc Centre ◽  
Local Reference ◽  
North Polar

Aims. We aim to characterise the magnetism of a large fraction of the north polar region close to a maximum of activity, when the polar regions are reversing their dominant polarity. Methods. We make use of full spectropolarimetric data from the CRisp Imaging Spectro-Polarimeter installed at the Swedish Solar Telescope. The data consist of a photospheric spectral line, which is used to infer the various physical parameters of different quiet Sun regions by means of the solution of the radiative transfer equation. We focus our analysis on the properties found for the north polar region and their comparison to the same analysis applied to data taken at disc centre and low-latitude quiet Sun regions for reference. We also analyse the spatial distribution of magnetic structures throughout the north polar region. Results. We find that the physical properties of the polar region (line-of-sight velocity, magnetic flux, magnetic inclination and magnetic azimuth) are compatible with those found for the quiet Sun at disc centre and are similar to the ones found at low latitudes close to the limb. Specifically, the polar region magnetism presents no specific features. The structures for which the transformation from a line-of-sight to a local reference frame was possible harbour large magnetic fluxes (>1017 Mx) and are in polarity imbalance with a dominant positive polarity, the largest ones (>1019 Mx) being located below 73° latitude.

Transient small-scale brightenings in the quiet Sun corona: a model for "campfires" observed with Solar Orbiter

2021 ◽  
Author(s):  
Yajie Chen ◽  
Damien Przybylski ◽  
Hardi Peter ◽  
Hui Tian
Keyword(s):  
Convection Zone ◽  
Extreme Ultraviolet ◽  
Small Scale ◽  
Coronal Emission ◽  
Lower Corona ◽  
Quiet Sun ◽  
Self Consistent ◽  
Before And After ◽  
Field Lines ◽  
The Magnetic Field

<div> <div> <div> <p>Recent observations by the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter have revealed prevalent small-scale transient brightenings in the quiet solar corona termed campfires. To understand the generation mechanism of these coronal brightenings, we constructed a self- consistent and time-dependent quiet-Sun model extending from the upper convection zone to the lower corona using a realistic 3D radiation MHD simulation. From the model we have synthesized the coronal emission in the EUI 174 Å passband. We identified several transient coronal brightenings similar to those in EUI observations. The size and lifetime of these coronal brightenings are 2–4 Mm and ∼2 min, respectively. These brightenings are located at a height of 2–4 Mm above the photosphere, and the surrounding plasma is often heated above 1 MK. These findings are consistent with the observational characterisation of the campfires. Through a comparison of the magnetic field structures before and after the occurrence of brightenings, we conclude that these coronal brightenings are generated by component magnetic reconnection between interacting bundles of field lines or the relaxation of highly twisted flux ropes. Occurring in the coronal part of the atmosphere, these events show no measurable signature in the photosphere. These transient coronal brightenings may play an important role in heating of the local coronal plasma.</p> </div> </div> </div>

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