Acceleration of lithium test ions in the quiet time geomagnetic tail

One of the active experiments to be performed as part of the Active Magnetospheric Particle Tracer Explorers mission involves the release of lithium ions in the geomagnetic tail and their subsequent detection after earthward convection into the nightside outer ring current region. In this paper we have used the guiding center approximation to integrate ion trajectories in a simple two‐dimensional model of the quiet time nightside magnetosphere in order to estimate expected ion properties at the latter location. Our principal conclusion is that under typical quiet time conditions these ions will predominantly form a field‐aligned beam (∼5°–20° pitch angle) at energies from a few hundred eV to ∼1 keV.