A Parametric Analysis of an Off-Axis Coaxial Bunched Electron Beam Space-Charge Limit

Recently, a nontrivial space-charge limit for off-axis bunched electron beams in a coaxial conducting structure was derived theoretically. The space-charge limit describes the minimum strength of an external uniform magnetic focusing field which is needed to stabilize the beam´s center-of-mass motion in the presence of induced surface charges on the coaxial structure. In this paper, we perform a parametric study of the space-charge limit to numerically determine its dependence on the conducting structure geometry, i.e., the ratio of the inner and outer conductor radii, as well as its dependence on the transverse and longitudinal bunch distributions.