The Side-Effects of the Space Charge Field Introduced by Hollow Electron Beam in the Electron Cooler of CSRm

TL;DR

This paper investigates the nonlinear electromagnetic effects of hollow electron beams in electron coolers, finding that these effects do not cause significant resonances for uranium ions in CSRm.

Contribution

It provides a detailed analysis of the tune shift, tune spread, and resonance driving terms caused by hollow electron beams, comparing them with solid beams.

Findings

Nonlinear fields from hollow beams do not induce serious resonances.

Differences between hollow and solid electron beams are characterized.

Calculations specific to uranium ions at 1.272 MeV in CSRm are presented.

Abstract

Electron cooler is used to improve the quality of the beam in synchrotron, however it also introduces nonlinear electromagnetic field, which cause tuneshift, tunespread and may drive resonances leading to beam loss. In this paper the tuneshift and the tunespread caused by nonlinear electromagnetic field of the hollow electron beam was investigated, and the resonance driving terms of the nonlinear electromagnetic field was analysed. The differences were presented comparing with the solid electron beam. The calculations were performed for $^{238}U^{32+}$ ions of energy 1.272MeV stored in CSRm, using the parameters given in table1. The conclusion is that in this situation nonlinear field caused by the hollow electron beam do not lead to serious resonances.