Single Bunch Monopole Instability

Single Bunch Stability to Monopole Excitation

Single-bunch Instability of Positron Beams in Electron Cloud

Single-bunch instability of a short and dense positron beam in a photo-electron plasma is studied numerically using code LCODE. The code was originally developed for studies of plasma wakefield acceleration. It is twodimensional and fully relativistic, with both the beam and electrons modelled by macro-particles. The instability is shown to affect the rear part of the beam, right after the arri...

1 . 1 Single bunch instabilities induced by electron cloud in short positron / proton / ion bunches

1.1.1 Introduction For linear accelerators, a single bunch instability of a positron bunch due to electrons created by ionization of the residual gas was discussed in Ref. [1], where a coherent oscillation of both electrons and positrons grows from any small initial perturbation of the bunch distribution, e.g. from the statistical fluctuations due to the finite number of beam particles. This in...

Measurements of Bunch Motion Due to the Longitudinal Dipole-Coupled Bunch Instability at the Cornell Electron-Positron Storage

In the past a longitudinal dipole-coupled bunch instability had limited high current operation at CESR and resulted in a degradation of luminosity performance. A longitudinal feedback system successfully damps this instability and the exchange of superconducting rf cavities for normal conducting rf cavities in CESR has further reduced the instability's strength. A description of the longitudina...

Observation of Beam Ion Instability in Spear3*

Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum...