The impact of persistent current field errors on the stability of the proton beam in the HERA proton ring

The field error of the HERA magnets are examined with reference to the stability of the proton beam. The dynamics of the proton beam under the influence of the strong persistent field errors and the correction and compensation scheme of HERA is presented and discussed. It is concluded that the field quality of the HERA superconducting magnets is remarkably good. Unavoidable strong systematic persistent current sextupolar, decapolar, and dodecapolar field errors have to be compensated for by compensation coils. Differences between the production lines do not cause problems due to ordered sequences of magnet installations. Simulations of single particle stability of a proton beam in HERA at injection energy promise sufficient aperture for stable synchrobetatron oscillations. First results from the commissioning of the HERA proton ring are presented. It has been demonstrated that a proton beam can be stored in HERA at 40 GeV with a reasonable lifetime.<>