Related papers: Micro-events in the active and quiet solar corona
In this paper, we use a highly sensitive telescope to characterize solar X-ray transients ranging from microflares in active regions down to weakly energetic brightenings in the quiet Sun. X-rays are closely linked to the initial energy…
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…
X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…
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…
New instruments sensitive to chromospheric radiation at X-ray, UV, Visible, IR, and sub-mm wavelengths have become available that significantly enhance our ability to understand the bi-directional flow of energy through the chromosphere. We…
Weak heating events are frequent and ubiquitous in solar corona. They derive their energy from the local magnetic field and form a major source of local heating, signatures of which are seen in EUV and X-ray bands. Their radio emission…
The energy that heats the magnetically closed solar corona originates in the complex motions of the massive photosphere. Turbulent photospheric convection slowly displaces the footpoints of coronal field lines, causing them to become…
Brightenings observed in the solar extreme-ultraviolet (EUV) images are generally interpreted as signatures of micro- or nanoflares occurring at the transition region or coronal temperatures. Recent observations with the Extreme Ultraviolet…
The Sun's corona is millions of degrees hotter than its 5,000 K photosphere. This heating enigma is typically addressed by invoking the deposition at coronal heights of non-thermal energy generated by the interplay between convection and…
Parker (1972) first proposed that coronal heating was the necessary outcome of an energy flux caused by the tangling of coronal magnetic field lines by photospheric flows. In this paper we discuss how this model has been modified by…
Spicules have been proposed as significant contributors to the mass and energy balance of the corona. While previous observations have provided a glimpse of short-lived transient brightenings in the corona that are associated with spicules,…
We report the smallest coronal jets ever observed in the quiet Sun with recent high resolution observations from the High Resolution Telescopes (HRI-EUV and HRI-Ly{\alpha}) of the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter. In…
The coronal heating problem remains one of the most challenging questions in solar physics. The energy driving coronal heating is widely understood to be associated with convective motions below the photosphere. Recent high-resolution…
The excess temperature of the solar corona over the photosphere poses a challenge. Multiple energetic events contribute to maintaining the corona at such high temperatures. The energy released in different events can vary across several…
The solar corona has been revealed in the past decade to be a highly dynamic nonequilibrium plasma environment. Both the loop-filled coronal base and the extended acceleration region of the solar wind appear to be strongly turbulent, but…
Understanding the relationship among different emission components plays an essential role in the study of particle acceleration and energy conversion in solar flares. In flares where gradual and impulsive emission components can be readily…
Decades of solar coronal observations have provided substantial evidence for accelerated particles in the corona. In most cases, the location of particle acceleration can be roughly identified by combining high spatial and temporal…
Based on simultaneous observations of solar flares in hard and soft X-rays we studied several aspects of the Neupert effect. About half of 1114 analyzed events show a timing behavior consistent with the Neupert effect. For these events, a…
The energy released during solar flares is believed to be stored in non-potential magnetic fields associated with electric currents flowing in the corona. While no measurements of coronal electric currents are presently available, maps of…
The opening-up of the magnetic field during solar eruptive events is often accompanied by a dimming of the local coronal emission. From observations of filament eruptions recorded with the Extreme-Ultraviolet Imager on STEREO during…