Adiabatic Focuser with Ion Motion

In this paper, after reviewing the concept of an adiabatic focuser we numerically study the effect of ion motion. Our work has been motivated by a recent suggestion that ion motion in an adiabatic focuser might be significant and even preclude operation of the focuser as previously envisioned. It is shown that for parameters associated with cases in which the adiabatic lens would be used, despite ion motion, the adiabatic focuser should work as well as originally envisioned. We then extend the study by considering a very long electron pulse (which accentuates the effect of ion motion).