TRANSVERSE WAKE FIELDS DUE TO NONAXISYMMETRIC DRIVE BEAMS IN THE DIELECTRIC WAKE-FIELD ACCELERATOR

The transverse wake fields in a dielectric wake-field accelerator are calculated for the case of an off-axis drive beam. The calculation is done taking into account the transverse dimensions of the wake-field structure including the ratio of inner to outer radii of the dielectric liner S. The results indicate that the m = 1 radial transverse wake-field component is much smaller than the m = 0 axial wake field for liners with small hole size (S less-than-or-equal-to 0.2). Therefore, beam breakup instabilities can be avoided, even for large drive beam currents, in dielectric wake-field accelerators where S is small.