The electron multipacting is an important factor for the development of the electron cloud. There is a trailing-edge multipacting in the tail of the long-bunch beam. It can be described by the energy gain and motion of electrons. The analyses are in agreement with the simulation.
Cite
@article{arxiv.1509.07661,
title = {Electron multipacting in long-bunch beam},
author = {Li Kai-Wei},
journal= {arXiv preprint arXiv:1509.07661},
year = {2015}
}