Mutual compensation of wakefield and chromatic effects of intense linac bunches

Mutual compensation of transverse and chromatic effects for intense electron bunches in a high-energy linac is a recent Novosibirsk idea which provides a new control of emittance enlargement. In this paper the authors elaborate on the principles and constraints for this new technique which requires careful matching of internal bunch parameters with external forces. With specific values of the bunch length, bunch intensity, and klystron phasing, the transverse-wakefield-induced forces within the bunch can be canceled by energy-dependent forces from the quadrupole lattice at all positions along the linac. Under these conditions the tolerances for quadrupole alignment, dipole stability, and injection launch errors are significantly relaxed