Emittance Dilution due to Dipole Mode Rotation and Coupling in the Main Linacs of the ILC

The progress of multiple bunches of charged particles down the main L-band linacs of the ILC (International Linear Collider) can be disrupted by wakefields. These wakefields correspond to the electromagnetic fields excited in the accelerating cavities and have both long-range and short-range components. The horizontal and vertical modal components of the wakefield will be excited at slightly different frequencies (the dipole mode frequency degeneracy’s are split) due to inevitable manufacturing errors. We simulate the progress of the ILC beam down the collider under the influence of these wakefields. In particular, we investigate the consequences on the final emittance dilution of the beam of coupling of the horizontal to the vertical motion of the beam.