Coulomb coherent beam oscillations in multi-aperture LINAC

In a multi-aperture LINAC Coulomb coherent beam oscillations are excited and thus stimulate particle losses. To analyse coherent oscillations a model is proposed, in which the Coulomb fields of 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 a multi-aperture alternating phase focused LINAC are studied. The dipole mode is shown to result in particle losses in peripheral channels of an example LINAC, while increasing of bunch sizes by the quadrupole mode is negligible. (orig.)