Related papers: Static and Impulsive Models of Solar Active Region…

Recent progress in obtaining high spatial resolution images of the solar corona in the extreme-ultraviolet (EUV) with Hinode, TRACE, SDO and recent Hi-C missions and soft X-ray (SXR) bands opened a new avenue in understanding the solar…

Recent simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high temperature emission observed at soft X-ray wavelengths using static heating models.…

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Nanoflares are believed to be key contributors to heating solar non-flaring active regions, though their individual detection remains challenging. This study uses a data-driven field-aligned hydrodynamic model to examine nanoflare…

EUV observations of warm coronal loops suggest that they are bundles of unresolved strands that are heated impulsively to high temperatures by nanoflares. The plasma would then have the observed properties (e.g., excess density compared to…

The Soft X-ray intensity of loops in active region cores and corresponding footpoint, or moss, intensity observed in the EUV remain steady for several hours of observation. The steadiness of the emission has prompted many to suggest that…

Determining the preferred spatial location of the energy input to solar coronal loops would be an important step forward towards a more complete understanding of the coronal heating problem. Following on from Sarkar & Walsh (2008) this…

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…

The Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) and the Hinode/ EUV Imaging Spectrometer (EIS) observed AR 11726 on 2013 April 23. We present intensity images in numerous atomic lines constructed from these observations. These…

The high densities, long lifetimes, and narrow emission measure distributions observed in coronal loops with apex temperatures near 1 MK are difficult to reconcile with physical models of the solar atmosphere. It has been proposed that the…

Much evidence suggests that the solar corona is heated impulsively, meaning that nanoflares may be ubiquitous in quiet and active regions (ARs). Hard X-ray (HXR) observations with unprecedented sensitivity $>$3~keV are now enabled by…

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…

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…

Context: One of the most prominent processes suggested to heat the corona to well above 10^6 K builds on nanoflares, short bursts of energy dissipation. Aims: We compare observations to model predictions to test the validity of the…

The nanoflare paradigm of coronal heating has proven extremely promising for explaining the presence of hot, multi-million degree loops in the solar corona. In this paradigm, localized heating events supply enough energy to heat the solar…

All three components of the current density are required to compute the heating rate due to free magnetic energy dissipation. Here we present a first test of a new model developed to determine if the times of increases in the resistive…

We use the cellular automaton model described in L\'opez Fuentes \& Klimchuk (2015, ApJ, 799, 128) to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields,…

It is largely agreed that many coronal loops---those observed at a temperature of about 1 MK--- are bundles of unresolved strands that are heated by storms of impulsive nanoflares. The nature of coronal heating in hotter loops and in the…

Observational measurements of active region emission measures contain clues to the time-dependence of the underlying heating mechanism. A strongly non-linear scaling of the emission measure with temperature indicates a large amount of hot…

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…