Related papers: Cooling Active Region Loops Observed With SXT and …
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…
In the last 30 years, the existence of small and cool magnetic loops (height < 8 Mm, T < 10^5 K) has been proposed and debated to explain the increase of the DEM (differential emission measure) towards the chromosphere. We present…
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…
We analyze and model a C5.7 two-ribbon solar flare observed by SDO, Hinode and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV…
The heating of the outer solar atmospheric layers, i.e., the transition region and corona, to high temperatures is a long standing problem in solar (and stellar) physics. Solutions have been hampered by an incomplete understanding of the…
Strong evidence exists that coronal loops as observed in EUV and soft X-rays may not be monolithic isotropic structures, but can often be more accurately modeled as bundles of independent strands. Modeling the observed active region…
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…
Many models for coronal loops have difficulty explaining the observed EUV brightness of the transition region, which is often significantly less than theoretical models predict. This discrepancy has been addressed by a variety of approaches…
The quiet solar corona consists of myriads of loop-like features, with magnetic fields originating from network and internetwork regions on the solar surface. The continuous interaction between these different magnetic patches leads to…
MHD kink instability can trigger the fragmentation of a twisted magnetic flux tube into small-scale current sheets that dissipate as aperiodic impulsive heating events. This instability propagates as an avalanche to nearby flux tubes and…
The EUV Imaging Spectrometer (EIS) on the Hinode satellite is capable of measuring emission line center positions for Gaussian line profiles to a fraction of a spectral pixel, resulting in relative solar Doppler-shift measurements with an…
Using detrended fluctuation analysis (DFA) and rescaled range (R/S) analysis, we investigate the scaling properties of EUV intensity fluctuations of low-latitude coronal holes (CHs) and neighboring quiet-Sun (QS) regions in signals obtained…
We investigate the scaling properties of the long-range temporal evolution and intermittency of SDO/AIA intensity observations in four solar environments: an active region core, a weak emission region, and two core loops. We use two…
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…
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…
The SDO EUV observations have revealed interesting characteristics of warm coronal emissions, which peak soon after the hot coronal X-ray emissions peak during a flare and then sometimes peak for a second time hours after the X-ray flare…
Results from the Solar Maximum Mission showed a close connection between the hard X-ray and transition region emission in solar flares. Analogously, the modern combination of RHESSI and IRIS data can inform the details of heating processes…
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…
In order to understand solar atmospheric heating it is important to test heating models against spatially resolved data from solar active regions. Here we model a small active region, AR~12760 observed on 2020 April 28, with the GX…
Recent observations from the Interface Region Imaging Spectrograph (IRIS) have discovered a new class of numerous low-lying dynamic loop structures, and it has been argued that they are the long-postulated unresolved fine structures (UFS)…