“Thick-Slice” simulation of short longitudinal-scale phenomena on a space-charge-dominated beam

Publisher Website
Google Scholar
Abstract
Simulations examining the propagation of a beam with a transverse temperature somewhat greater than the longitudinal temperature have shown evidence that the beam can evolve towards temperature isotropy via a collective electrostatic instability. Because the longitudinal scale of the unstable modes is comparable to the beam diameter, simulation of this instability with sufficient axial resolution can be costly, particularly in an alternating-gradient transport channel where the geometry is inherently three-dimensional. A “thick-slice” model has therefore been developed which extends the usual single-slice approximation to include a self-consistent solution for the longitudinal fields within the slice, while still assuming that the external forces act simultaneously on all particles in the slice. An example of the use of this method is presented to illustrate how the fundamental dynamics of the isotropization instability appear to be preserved even in the presence of the large excursions in the beam envelope which are present in a beam matching system.

This publication has 0 references indexed in Scilit: