Understanding the solar atmosphere, which connects to the heliosphere via radiation, the solar wind and coronal mass ejections, and energetic particles is pivotal for establishing the conditions for life and habitability in the solar system. SOLAR-C (EUVST) (EUV High-Throughput Spectroscopic Telescope) is designed to comprehensively understand the energy and mass transfer from the solar...
The 3D extensions to the Standard model of solar flares have been succcessfull in explaining various observed phenomena. Among them, there are (1) hot cores (sigmoids), (2) apparent slipping motion of flare looops, (3) saddle-shaped flare arcades, as well as (4) reconnection of the drifting flux rope with the surrounding corona or itself during the eruption. We review the properties of the 3D...
During solar flares, the impulsive release of magnetic energy drives plasma heating, fast flows, and intense brightening across the spectrum. Current models of solar flares are able to accurately reproduce many key observables, including the speed of chromospheric evaporation flows, plasma densities and atomic line intensities. However, after the cessation of impulsive heating, the models...
To understand the trigger of solar flares and eruptions it is necessary to obtain an accurate description of the 3D pre-eruptive coronal magnetic configuration. The latter is not directly observable and one must rely either on static modelling/extrapolation from 2D photospheric measurements, and/or on relatively idealized time-evolution of a magnetic model from numerical simulations. The...
Solar flares are transient yet dramatic events in the atmospheres of the Sun, during which vast amounts of magnetic energy is liberated. This energy is subsequently transported through the solar atmosphere or into the heliosphere, and together with coronal mass ejections flares comprise a fundamental component of space weather. Thus, understanding the physical processes at play in flares is...
Solar flares are amongst the most energetic events in our solar system. Accompanied by intense UV and X-ray emissions, energetic particles and coronal mass ejections can be injected into the interplanetary medium during flares. As these various aspects can have a large impact on solar system bodies and a detrimental effect on human activities, there is a strong interest to gain a deeper...
Solar coronal jets are observed as collimated plasma flows with high velocity along magnetic field lines in a wide wavelength range, from X-rays to EUV. Occasionally these hot jets are closely related to cool surges, which are chromospheric ejections that emerge in the form of unwrinkled threads. Though these phenomena have been studied over the past few decades with different instruments and...
The overall paradigm of flare energy release is well-known. An energy-bearing coronal magnetic field relaxes via magnetic reconnection to a lower energy state, and the energy released is converted and dissipated in the radiation flash that is a solar flare. But what does that energy conversion and energy dissipation involve? There are strong and long-standing pointers to an important role for...
Magnetic reconnection governing energy release in solar flares takes place in the corona; the lower atmosphere responds rapidly to energy transfer from the corona, generating prominent radiation and dynamic signatures that help us infer properties of energy release and transfer. Fine-scale structures embedded in the generally curvilinear-shaped flare ribbons indicate the global organization of...
According to our current understanding, solar flares are driven by magnetic energy stored in the solar corona being rapidly released through a process involving magnetic reconnection. This scenario was originally proposed on the basis of classic observations including radio and hard X-ray emission from non-thermal electrons accompanying rising emission from hot thermal plasma. Over the past...
Coronal mass ejections (CMEs) are the largest scale eruptions of plasmas in the solar corona. Many observations show that pre-eruptive CMEs always appear as bright structures in EUV high-temperature bands and rise slowly when approaching the onset of their eruption. However, the mechanisms behind these phenomena are still puzzling. In this work, we aim to explore these by combining...
We discuss the current state of MHD modeling of solar flares and eruptions. We focus on models that yield synthetic observables accessible to current and future generations of remote sensing capabilities, such as MUSE, EUVST and ground-based observatories. A critical assessment of the successes and limitations of current models with be presented, as well as suggestions for paths going forward.
Solar active regions are thought to be formed by the emergence of magnetic flux from the deep convection zone and, therefore, it is important to use a large computational domain covering the entire convection zone to understand the physics behind. However, the high acoustic speed makes it difficult to conduct magnetohydrodynamic simulations in such a deep domain. The R2D2 code overcomes this...
Unresolved mass motions are frequently detected in flares from extreme ultraviolet (EUV) observations, which are often regarded as turbulence. Non-thermal broadening of EUV emission lines caused by turbulence can be found at the entire flare region including flare loop top, legs, footpoints and the region above the looptop. Peaks in non-thermal velocity values tend to show up above the high...
