Calculations of the conditions for bunched-beam e-p instability in the Los Alamos Proton Storage Ring (PSR)

Recent observations are consistent with the possibility of an electron-proton instability in the Proton Storage Ring (PSR), with both a bunched and an unbunched beam. This instability requires stable trapping of electrons within the space charge potential of the protons and such trapping is not expected with a bunched beam at PSR parameters. However, it is shown that electron trapping can occur if some of the beam leaks into the interbunch gap. Such leakage is observationally associated with the instability. Also, it is shown that the leakage is consistent with the expected longitudinal dynamics within the PSR. Implications for improving PSR stability are discussed.<>