A 3D MHD‐Particle Tracing Model of Na ⁺ Energization on Mercury's Dayside

Data collected by the Fast Imaging Plasma Spectrometer (FIPS) aboard MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft showed singly charged Na+-group ions at energies of between 1 13 keV in Mercury's northern planetary cusp. Most these are likely formed either photoionization or charge exchange exospheric Na atoms, with initial approximately eV less. FIPS observations did not establish which acceleration mechanism most reasonably accounts for this energy gain. Using Adaptive Mesh Particle Simulator (AMPS) model, we undertake kinetic simulations Na+ test particles through electric magnetic fields output from Block Tree Solar wind Roe-type Upwind Scheme (BATSRUS) global magnetohydrodynamic (MHD) model magnetosphere, search plausible explanations source energization. We find that readily picked up Dungey cycle return flow dayside magnetosphere. In some cases, provides to escape into magnetosheath, other cases it energizes hundreds before they pass immediately Those can be rapidly magnetosheath flow, where accelerated pickup again tens keV. These one- two-stage processes on account many observed magnetospheric cusp MESSENGER.