Axially non-uniform beam-tunnel geometries preserving the cross-section of a sheet beam

Abstract

In this work, we study in a system with weak axial non-uniformity, the required shape of the beam-tunnel boundary, so that the cross-section of a non-axisymmetric electron beam is preserved, in spite of the E/spl times/B drift. For a beam with elliptic cross section (including the limit of a sheet beam), the Poisson equation has been solved to first order in the non-uniformity, thus defining the suitable shape of the beam tunnel boundary.