The problem of ion trapping in the high-energy storage ring HESR is
studied in the present report. Positive ions are trapped in the negative
potential well of the antiproton beam. The ions are produced by the
interaction between the antiproton beam and the residual gas. The adverse
effects of ion trapping like tune shifts, tune spreads and coherent
instabilities are reviewed. The ion production rate by ionization of the
residual gas molecules is estimated. The negative potential well and the
corresponding electric fields of the antiproton beam are evaluated in order
to study the transverse and longitudinal motion of the ions and the
accumulation in trapping pockets. The removal of ions can be achieved
using clearing electrodes and under certain conditions resonant transverse
beam shaking. Diagnostic tools and measurements of trapped ion
effects are sketched
