Periodic four-dimensional solution for transport of intense and coupled coasting beams through quadrupole channels

Imposing angular momentum to a particle beam increases its stability against perturbations from space charge [Y.-L. Cheon et al., Phys. Rev. Accel. Beams 25, 064002 (2022)]. In order to fully explore this potential, proper matching of intense coupled beams along regular lattices is mandatory. Herein, a novel procedure assuring matched transport is described and benchmarked through simulations. The concept of matched transport along periodic lattices has been extended from uncoupled beams to those with considerable coupling between the two transverse degrees of freedom. For coupled beams, matching means the extension of cell-to-cell periodicity from just transverse envelopes to the coupled beam moments and to quantities being derived from these.