Highlights:

Solar atmosphere ejections.

There are still many open questions concerning key ejections in the solar atmosphere such as coronal jets, surges or spicules. We have addressed different aspects of these phenomena. For instance, we have showed that  the characteristics of observed surges and kernels (plasmoids) that accompany coronal jets, as well as the detected double-chambered structures, show striking similarities with numerical jet models (Joshi et al. 2020). We have also studied the impact of coronal jets on prominences both from the theoretical side through 2.5D numerical simulations (Luna & Moreno-Insertis, 2021) and from multi-wavelength observations (Joshi et al. 2023), obtaining results that are in general agreement. With respect to surges, we have characterized for the first time the chromospheric and transition region properties of these phenomena combining high-resolution observations and advanced techniques such as k-means, inversions and density diagnostics (Nóbrega-Siverio et al. 2021). In addition, we have involved in the understanding of the coronal and transition region responses to the recently reported chromospheric downflowing rapid red shifted excursions (RREs, Bose et al. 2021). More recently, we have used coordinated SST, IRIS and SDO observations to analyze an ephemeral magnetic flux emergence episode and the following chain of small-scale energetic events, demonstrating the importance of high-resolution magnetograms in revealing the mechanisms that trigger phenomena such as EB, UV bursts and surges (Nóbrega-Siverio et al. 2024). Similar coordinated observations approach is used to reveal key aspects of the jet driven by magnetic reconnection in regions of mixed polarity, where evolving magnetic topologies, including flux ropes and null points, trigger both hot and cool jets. These jets display widening, untwisting motions, and plasma fallback, with reconnection sites moving along magnetic field lines, suggesting that such dynamic features are typical of impulsive jets across different solar environments (Joshi et al. 2024a, 2024b).

Coronal rain.

Another aspect studied within the Whole Sun project is flare-driven coronal rain. Using a resistive magnetohydrodynamics (MHD) simulation with the MPI-AMRVAC code, we have explored the evolution of magnetic flux ropes that give rise to eruptions and coronal rain formation. The model captures the formation and eruption of a series of magnetic flux ropes in a self-consistent manner due to spontaneous magnetic reconnection across current sheets which are created underneath the erupting flux ropes. In the post-eruption phase, a gradual development of a thermal imbalance is noticed that leads to a catastrophic cooling and the formation of condensations that slides down along the magnetic field lines in the form of coronal rain. The dynamical and thermodynamic properties of these cool-condensations agree well with observations of post-flare coronal rain in the solar atmosphere (Sen et al. 2024).

Nonequilibrium and partial ionization.

We have studied the effects of nonequilibrium and partial ionization in the dynamics and thermodynamics of new magnetized plasma emerging from the solar interior through numerical experiments (Nóbrega-Siverio et al. 2020a). To that end, it was necessary to implement a new Fortran module in the Bifrost code that calculates the ambipolar diffusion term in the Generalized Ohm's Law in an efficient way (Nóbrega-Siverio et al. 2020b). Recently, we have explored the ambipolar diffusion term from a more fundamental and mathematical perspective, finding new sets of self-similar solutions that can be used as demanding tests for MHD codes that include the ambipolar diffusion term, both in cylindrical coordinates (Moreno-Insertis et al. 2022) and in cartesian ones (Moreno-Insertis et al. to be submitted). 

Coronal Bright Points (CBPs).

We have recently presented a comprehensive 3D radiative-MHD model using the Bifrost code of a CBP based on a magnetic nullpoint configuration, a common topology related to this kind of phenomena. We have shown that CBPs can be energized, for at least several hours, through the continuous action of stochastic photospheric convective motions, thus obviating the need for major, organized photospheric flows such as converging flows or large-scale surface flows. We have also detected continuous upflows with faint EUV signal related to the CBP, resembling observational dark coronal jets, and small-scale eruptions when chromospheric fibrils interact with the reconnection site (Nóbrega-Siverio et al. 2023).

We have also explored the chromospheric counterpart of CBPs, from observations as well as simulations, providing further understanding on the heating of the plasma confined in the small-scale loops of the CBPs and on the chromosphere underneath CBPs (Madjarska et al. 2021, Bose et al. 2023, Nóbrega-Siverio and Moreno-Insertis 2022). 

Magnetic reconnection.

In this project we have also implemented different resistivity models to the radiate-MHD Bifrost code to study their impact in the magnetic reconnection process and to study which one is more suitable to reproduce solar features and the potential diagnostics from different current and future space missions (Faerder et al. 2023, Faeder et al. 2024a, Faeder et al. 2024b). 

Solar satellites.

We have contributed to the review of the Interface Region Imaging Spectrograph (IRIS, De Pontieu et al. 2021), focusing on the key aspects that this satellite has contributed to the better understanding of the formation and impact of spicules and other jets.

In addition to that, we have contributed in two papers related to the Multi-slit Solar Explorer (MUSE), which is a proposed NASA MIDEX mission. Our role has been providing synthetic observables from our realistic simulations with the aim of showing the potential capabilities of diagnostics of the mission (see De Pontieu et al. 2022 and Cheung et al. 2022).