Prediction of entry paths of solar wind ions into the inner magnetosphere using a toy model

Finding entry paths for, and energization mechanisms of solar wind ions into and within Earth’s inner magnetosphere are discussed in this presentation. The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on the twin Van Allen Probes spacecraft measures energetic charged particles [~20 keV to ~1 MeV] in the inner magnetosphere and ring current. We have identified a number of RBSPICE measurements with clear higher charge state oxygen (O^5/6+) and helium (He²⁺) ion injection events, and deployed a fully kinetic toy model to track the particles forward and backward in time. The model is based on the time-dependent TS07D model for the magnetic field structure. We imposed a transient artificial electric field in the nightside magnetosphere of various amplitudes in order to further track the particles to the entry regions in the outer magnetosphere and understand the variations required for best interplanetary access. The model shows that initial particle departure and entry path can greatly vary by the particle’s phase angle (as measured in the plane perpendicular to the local magnetic field), as well as the imposed potential drops. Possible effects of scattering processes have been ignored in our simulations. Additionally, results of the forward modeling simulation will be presented to show estimates of ion energization rates as ions drift through the magnetosphere.