Solar flares are among the most energetic events in our solar system, converting magnetic energy into heat and accelerating particles to high energies. Their large-scale evolution is often well described by magnetohydrodynamics (MHD), which treats the plasma as a conducting fluid. However, in the central reconnection region—where magnetic field lines break and reconfigure—the MHD approximation fails. Here, kinetic effects dominate, requiring a fully kinetic approach such as particle-in-cell (PIC) to capture the physics accurately. Understanding the interaction between these two regimes—fluid and kinetic—is crucial for modeling energy release and particle acceleration in solar and astrophysical plasmas.
To address this challenge, we use DISPATCH, a high-performance simulation framework designed for adaptive, multi-physics modeling. DISPATCH decomposes the computational domain into independent, asynchronously evolving patches, enabling dynamic solver switching. This means that different physical models—such as MHD and fully kinetic PIC—can be deployed in different regions of the same simulation, ensuring computational efficiency while capturing the relevant physics.
In this talk, I will present our recent implementation of an embedded PIC-MHD coupling within DISPATCH. I will outline the core principles of this approach, discuss its computational efficiency, and validate it through benchmark test cases. Finally, I will showcase a semi-realistic solar flare simulation where the PIC solver is selectively applied to the reconnection region, capturing both large-scale MHD evolution and small-scale particle acceleration within a single framework. This work highlights how adaptive multi-physics simulations can be leveraged to study fundamental plasma processes not only in the solar corona but also in broader astrophysical contexts.
