| Presentation Title: | Modeling Electron and Proton Acceleration in Macroscale Magnetic Reconnection |
| Author(s): | Zhiyu Yin, James F. Drake, Marc Swisdak |
Abstract:
Magnetic reconnection, the drive mechanism of solar flares, rapidly converts the stored magnetic energy in the Sun's corona into high speed flows and energetic electrons and ions. Simulations and models of reconnection suggest that plasma energization is controlled by Fermi acceleration during the growth and merger of macroscale magnetic flux ropes rather than acceleration in kinetic-scale boundary layers. The computational model kglobal is a hybrid MHD/particle model that eliminates all kinetic scales and has been developed to explore particle energization in macroscale reconnecting systems relevant to solar flare dynamics. The model, which initially only included non-thermal (energetic) electrons, has now been extended to include non-thermal ions. Reconnection simulations in macrosystems produce powerlaw spectra of electrons and protons that extend nearly three decades in energy with maximum energies of around an MeV for electrons and 5 MeV for protons. Particle energy gain is dominated by the growth and merger of large numbers of flux ropes. Protons typically gain more energy than electrons, with the powerlaw spectra of electrons reaching lower energies than that of protons. As in earlier electron-only kglobal simulations (Arnold et al 2021), the ambient guide field is the key factor that controls energization, with the strongest acceleration taking place with weak guide fields. The kglobal model is being benchmarked with in situ PSP observations of a reconnection event in the heliospheric current sheet that produced a powerlaw spectrum of protons extending up to 500 keV (Desai et al 2024) .