Transverse Beam Dynamics in Plasma-based Linacs

The transverse beam dynamics in plasma channels of possible future plasma-based linacs is discussed. We represent the transverse focusing of both a beam-driven and a laser-driven plasma wake eld accelerator by a uniform focusing channel. The transverse beam sizes and a basic o set tolerance are calculated, nding that sub-micron beams must be transported with even smaller o set tolerances. The results emphasize the need to pursue further ideas for plasma structures with high acceleration gradients but reduced transverse wake elds.