The effects of Coulomb beam interaction in multiaperture linac

In a multiaperture linac the Coulomb coherent beam oscillations are excited and thus stimulate particle losses. To analyse the coherent oscillations a model is proposed, in which the Coulomb fields of the surrounded beams in relation to the considered bunch train are approximated by the fields of uniformly charged threads. The low order mode equations are derived by linearization of the Coulomb and external fields. Beam interaction effects in the multiaperture alternating phase focused linac are studied. The dipole mode is shown to influence mainly the beam dynamics in this linac, and the increase of bunch size by quadrupole modes is negligible.< >