Ion-Hose Instability in Long Pulse Induction Accelerators

TL;DR

This paper investigates the ion-hose instability in long-pulse induction accelerators, analyzing its growth, saturation, and effects on beam stability through analytical and numerical methods.

Contribution

It provides new analytical and numerical insights into the nonlinear growth and saturation of the ion-hose instability for various ion frequency distributions.

Findings

Ion-hose instability limits vacuum quality in accelerators.

Beam envelope oscillations influence instability growth.

Saturated nonlinear growth characterized for different ion distributions.

Abstract

The ion-hose (or fast-ion) instability sets limits on the allowable vacuum in a long-pulse, high current accelerator. Beam-induced ionization of the background gas leads to the formation of an ion channel which couples to the transverse motion of the beam. The instability is studied analytically and numerically for several ion frequency distributions. The effects of beam envelope oscillations on the growth of the instability will be discussed. The saturated non-linear growth of the instability is derived analytically and numerically for two different ion frequency distributions.