Related papers: Spectroscopic Observations of Current Sheet Format…
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…
From pulsar scintillations we infer the presence of sheet-like structures in the ISM; it has been suggested that these are current sheets. Current sheets probably play an important role in heating the solar corona, and there is evidence for…
In this paper, we study the energy conversion and spectra in a corona current sheet by 2.5-dimensional MHD numerical simulations. Numerical results show that many Petschek-like fine structures with slow-mode shocks mediated by plasmoid…
We studied the dynamics of the solar atmosphere in the region of a large quiet-Sun filament, which erupted on 21 October 2010. The filament eruption started at its northern end and disappeared from the H$\alpha$ line-core filtergrams line…
We investigate the plasma and magnetic environment of active region NOAA 11261 on 2 August 2011 around a GOES M1.4 flare/CME (SOL2011-08-02T06:19). We compare coronal emission at (extreme) ultraviolet and X-ray wavelengths, using SDO AIA…
On October 3rd, 2024, the Sun emitted an X9.0-class flare from active region NOAA 13842. The event was recorded by multiple space-based instruments, beginning hours before the eruption, granting a unique opportunity to provide insight into…
Solar flares are complex phenomena driven by the release of magnetic energy, but a large energy reservoir is not sufficient to determine their eruptive potential; the magnetic topology and plasma dynamics play a key role. We investigate the…
The transition region between the Sun's corona and chromosphere is important to the mass and energy transfer from the lower atmosphere to the corona; consequently, this region has been studied intensely with ultraviolet (UV) and extreme…
We present direct evidence for the detection of the main energy release site in a non-eruptive solar flare, SOL2013-11-09T06:38UT. This GOES C2.7 event was characterised by two flaring ribbons and a compact, bright coronal source located…
We have carried out a comprehensive study of the temperature structure of plasmoids, which successively occurred in recurrent active region jets. The multithermal plasmoids were seen to be travelling along the multi-threaded spire as well…
Wide-field EUV telescopes imaging in spectral bands sensitive to 1 MK plasma on the Sun often observe extended ray-like coronal structures stretching radially from active regions to distances of 1.5-2Rsun, which represent the EUV…
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…
The sites of chromospheric excitation during solar flares are marked by extended extreme ultraviolet ribbons and hard X-ray footpoints. The standard interpretation is that these are the result of heating and bremsstrahlung emission from…
We have calculated the H$\alpha$ and Ca {\sc ii} 8542 {\AA} line profiles based on four different atmospheric models, including the effects of nonthermal electron beams with various energy fluxes. These two lines have different responses to…
We present observations and analysis of an X1.8 non-eruptive solar flare on 2012 October 23, which is characterized by an extremely large late-phase peak seen in the warm coronal extreme-ultraviolet (EUV) emissions ($\sim$ 3 MK), with the…
Coronal cavities have previously been observed associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to…
We model nanoflare heating of extrapolated active-region coronal loops via the acceleration of electrons and protons in Harris-type current sheets. The kinetic energy of the accelerated particles is estimated using semi-analytical and…
We report on X-ray flares that were observed from the active galactic nucleus I Zwicky 1 (I Zw 1) in 2020 January by the NuSTAR and XMM-Newton observatories. The X-ray spectrum is well-described by a model comprised of the continuum…
On the 29 March 2014 NOAA active region (AR) 12017 produced an X1 flare which was simultaneously observed by an unprecedented number of observatories. We have investigated the pre-flare period of this flare from 14:00 UT until 19:00 UT…
Between 2017 and 2024, the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory has observed numerous white-light solar flares (WLFs). HMI spectro-polarimetric observations of certain WLFs, in particular the X9.3…