Conveners
Energy and mass flow through the solar atmosphere – from solar campfires to CME (Observations and Theory)
- Hanna Strecker (Instituto de Astrofísica de Andalucía)
Energy and mass flow through the solar atmosphere – from solar campfires to CME (Observations and Theory)
- Sowmya Krishnamurthy (Max Planck Institute for Solar System Research)
Energy and mass flow through the solar atmosphere – from solar campfires to CME (Observations and Theory): Session 3B
- Shahin Jafarzadeh (Max Planck Institute for Solar System Research, Göttingen, Germany)
Energy and mass flow through the solar atmosphere – from solar campfires to CME (Observations and Theory)
- Alex Pietrow (AIP)
Energy and mass flow through the solar atmosphere – from solar campfires to CME (Observations and Theory)
- Ivan Milic ( Leibniz Institute for Solar Physics (KIS))
Continuous vector magnetic-field measurements by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) allowed us to run data-driven simulations of solar eruptions and perform statistical studies of magnetic-fields for many flares. In this talk I will review new aspects of flare magnetism discovered using SDO data, including progress in data-driven...
Solar flares originate from active regions (ARs) hosting complex and strong bipolar magnetic fluxes. Forecasting the probability of an AR to flare and defining reliable precursors of intense flares, i.e., X- or M-class flares, are extremely challenging tasks in the space weather field.
In this work, we focus on two metrics as flare precursors, the unsigned flux R* and the novel topological...
It is often observed that the Sun produces repetitive coronal mass ejections (CMEs) with similar morphological features originating from the same source region. This kind of CMEs is known as homologous CMEs and their occurrence is majorly controlled by the storage of free magnetic energy in the active region corona. The stored energy is catastrophically released during flares, accompanied by...
Coronal Mass Ejections (CMEs) are in the center of interest for solar - terrestrial research. They are interesting both from the fundamental plasma physical and space weather perspectives. The integral part of CMEs are huge magnetic flux ropes where magnetic field lines wind about a common axis. They form when magnetic energy first accumulates in the solar corona and then lose its balance....
Of the six remote-sensing instruments aboard Solar Orbiter, the Spectrometer/
Telescope for Imaging X-rays (STIX) is the one dedicated
to the study of solar flares. It performs imaging spectroscopy
in the hard X-ray regime, which provides key physical diagnostics on
both the hot thermal plasma as well as on the accelerated energetic
electrons. During its operation since launch in 2020,...
During the 8th call of the SOLARNET Trans-National Access Programme we were funded for a flare observing campaign at GREGOR (Tenerife). This campaign was supported by additional instruments, such as the IRIS and Hinode satellites, and ground-based instruments at the Astronomical Institute of the Czech Academy of Sciences in Ondřejov (CZ), and at the Białków Observatory of the University of...
In the era of Solar Orbiter and Parker Solar Probe, we have now an unprecedented view on eruptive events of the Sun, from their onset to their propagation in the heliosphere. Thanks to the proximity of the probes to the Sun for at least part of their orbit, we are currently acquiring more and more key data on the structuring and the propagation of solar eruptive events, as well as on the...
A multi-wavelength analysis is conducted to study flare signatures both in the
low and higher corona. LOFAR, STIX/Rhessi, and AIA data provide an extensive
picture about different aspects of flare characteristics. The active region and
its thermal evolution are studied through Differential Emission Measure (DEM)
reconstructions from AIA data. Flare-accelerated electrons and their...
Solar prominences consist of a thin thus low-collisional and partially ionized plasma.
Therefore, the coupling of ions and neutral atoms is much weaker than in photosphere,
and ions are affected by the Lorentz-force, while neutral atoms are not.
To investigate this issue, we performed simultaneous observations of the spectral lines
of several ions and neutral...
EUI is a set of (E)UV imaging telescopes that observe the solar corona from >10 Rsun scales down to pixel scales of 100 km. EUI has been embarked on the ESA/NASA Solar Orbiter mission on a 10-year mission, while the imaging cadence can be as fast as 2s. This wide range of spatial and temporal scales allows to observe the scale invariance of events, from the largest to the smallest flares, and...
The X1.6 flare observed on 22 October 2014 was one of the strongest flares observed in the complex active region NOAA 12192. We report on observations acquired in the Fe I 617.30 nm and Ca II 854.2nm line profiles by the Interferometric BIdimensional Spectropolarimeter (IBIS) immediately after the peak of the X1.6 flare. We focused on the chromospheric signals and studied the temporal...
Sun-as-a-star observations provide a valuable link between resolved solar observations and disk-integrated stellar observations, as it gives a unique insight into how well-defined solar activity affects the average spectrum. This activity can affect the integrated spectrum in complex ways, and therefore the values of for example reference spectra and exoplanet characterizations. It is...
Solar prominences consist of cool and dense plasma that is suspended in the corona, surrounded by hotter and less dense coronal material. As predecessors of coronal mass ejections, solar prominences are important drivers of space weather, but their exact formation mechanism is still unknown. We use the radiative magnetohydrodynamic code MURaM to simulate the formation and dynamics of a...
Recent ultraviolet observations performed by the IRIS satellite have shown the occurrence of small-scale eruptive phenomena, characterized by significant increase of the integrated line intensity (up to a factor of 100 in Si IV lines) and of the line width (up to ± 100 km s$^{-1}$), likely due to magnetic reconnection. Some of these events also exhibit counterpart in all the SDO/AIA...
On May 30, 2020, the Solar Orbiter High-Resolution Imager operating in 174 A being for the first time approximately at a half AU to the Sun, registered a large number of short, small-scale heating events, often called campfires, with rich morphology and smaller space-time characteristics than nanoflares. We estimate the thermal energy of the heating events from increases in the emission...
One-dimensional (1D) models of solar flares often generate hot upflows from the chromosphere (chromospheric evaporation) due to heating by energetic particle beams (Allred et al. 2005, 2015, Druett et al. 2017, Polito et al. 2023). The beams of particles are injected at the top of the models using distributions consistent with X-ray emission in observations assumed to result from...
The build-up of magnetic energy during flux emergence, which powers flares and coronal mass ejections (CME), requires the presence of significant amounts of volume electric currents. Measuring these electric currents requires knowledge of the magnetic field vector in three dimensions in the solar atmosphere. However, systematic high-quality spectropolarimetric observations are constrained at...
Xudong Sun- Formation and Destruction of Kilogauss Bald Patches in a Delta-Spot Light Bridge
Sibaek Yi- A New Method of Coronal Force-Free Field Reconstruction and Its Application to an Active Region
Salvo Guglielmino - Multi-instrument analysis of an eruptive M1.2 flare observed by Metis and STIX onboard Solar Orbiter
Tino L. Riethmüller - The potential of many-line inversions and an...
Observational precursors of small-scale solar flares provide a basis information for future operational systems for large events forecasting. We present the results of observational comparative study of the active flaring (AFR) and non-flaring regions (ANFR). We study power spectral density (PSD) of the intensity signal in the level of solar chromosphere and corona, through 2D-spatial maps of...
Understanding the physical processes in the solar chromosphere requires comprehensive models which can be compared to observations. These models include the treatment of magnetic fields, heat conduction and radiative transfer (RT). However, usually models fail to reproduce observed properties of chromospheric spectral lines. The MgII h&k lines form in the middle to upper chromosphere and are...
A new method is developed for construction of coronal force-free fields. This method employs a poloidal-toroidal representation of magnetic field, not only to ensure the divergence-free condition, but to straightforwardly implement the boundary conditions Bn and Jn at the coronal base. The performance of the computational code has been compared with that of other existing codes and is found to...
We contrast the mass loading and evolution of chromospheric fibrils with that of mottles, (the counterparts to fibrils found in regions with more vertically aligned B-field) in order to understand the flow of mass and the evolution of plasma elements passing between the layers of the solar atmosphere in a Bifrost simulation. We make use of the passive tracer particle module "corks" in order to...
Magnetic reconnection seems to be the central mechanism that powers solar flares by suddenly releasing magnetic energy. On the other hand Hall effect, the interaction between electric currents and the magnetic fields that surround them creates the conditions for fast magnetic reconnection. In the present research work, we perform a systematic comparison of 2.5D numerical resistive MHD...
Context. The smallest extreme-ultraviolet (EUV) brightening events that were detected so far, called campfires, have recently been uncovered by the High Resolution EUV telescope (HRIEUV), which is part of the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter. HRIEUV has a broad bandpass centered at 17.4 nm that is dominated by Fe ix and Fe x emission at about 1 MK.
Aims. We study...
On 25 March 2022, during the first perihelion of the Solar Orbiter Nominal Mission, the Metis coronograph observed a fast CME at the East limb, between 05:02 and 07:02 UT.
We were able to identify the source region of the ejection in active region NOAA 12974. This was observed on the solar disk by the SDO/AIA and Hinode/XRT instruments, enabling us to study the flaring event connected with...
We study transverse oscillations of plasma structures in the solar corona excited by vortex shedding solving the full set of the 3D ideal time-dependent magnetohydrodynamic equations. To present how the creation of vortices and excited oscillations depend on the initial flow speed and various values of the magnetic field, we performed a parametric study for two cases, an interaction of a...
Explosive phenomena are known to trigger a wealth of shocks in warm plasma environments, such as the solar chromosphere and molecular clouds, where the medium consists of both ionised and neutral species. Partial ionisation is critical in determining the behaviour of shocks, since the ions and neutrals locally decouple, allowing for substructure to exist within the shock. We study a switch-off...
Solar flares are among the most spectacular and energetic phenomena in the solar system, and understanding their driving mechanisms is of paramount importance in solar physics. It is widely accepted that magnetic reconnection is the primary mechanism behind solar flares. This process allows for the conversion of magnetic energy into plasma energy, resulting in the acceleration of particles...
Spicules are one of the most intriguing phenomena of the lower solar atmosphere. From our initial work on how solar p-modes may generate spicules (Nat. 2004), through using radial MHD simulations showing the formation of a forest of them (Nat. Phys. 2022), finally we are able to report a more unified theory of spicular physics, underpinned with solar observational and laboratory experimental...
Coronal bright points (CBPs) are systems of small, 1–3 MK hot loops, with lengths of about 10–20 Mm, and lifetimes of many hours. They are connected to bipolar magnetic field concentrations in the photosphere. CBPs are prominent and widespread in the quiet solar corona and coronal holes, best observed in the extreme-ultraviolet (EUV) and X-rays. Investigating their thermal structure will...
