Energy Conversion and Particle Acceleration in 3D Solar Flare Simulations

Recent observations and simulations indicate that solar flares undergo complex 3D evolution, making 3D particle transport models essential for understanding particle acceleration and interpreting flare emissions. Here, we investigate energy conversion and particle acceleration in solar flares using 3D MHD simulations coupled with energetic-particle transport models. The analysis identifies key acceleration regions—including the reconnection current sheet, termination shock, and supra-arcade downflows—as sources of turbulence and nonthermal particle production. Electrons and protons are efficiently accelerated to high energies, forming power-law spectra and exhibiting spatial distributions consistent with recent hard X-ray (HXR) and microwave (MW) observations. By selectively turning particle acceleration on or off in specific regions in controlled simulations, we find that different mechanisms work synergistically to produce a large population of accelerated particles. Our model produces time-dependent particle distributions in the flare region and at footpoints, enabling synthetic emission modeling to compare with observations and improve understanding of particle acceleration in 3D solar flare regions.