WG2021
LANL, Los Alamos, New Mexico, USA
LBNL, Berkeley, California, USA
High-brightness photoinjectors tend to produce electron beams with equipartitioned emittances, where the transverse normalized emittances are roughly the same as the normalized longitudinal emittance. However, the needs of future free-electron lasers will require transverse emittances up to three orders of magnitude smaller than the longitudinal emittances. Recent work on exotic optics schemes has pointed to significant new opportunities for providing arbitrary control of the beam emittance partitioning, based on the conservation of eigen-emittances which results from the symplectic behavior of electrodynamics. Specifically, we can use initial correlations imposed on the beam as it is formed to control the beam's eigen-emittances, which can then be recovered later at high energy as the actual beam emittances, in a linear sense. Here we discuss different schemes to provide arbitrary control of the eigen-emittances, including the addition of nonsymplectic beamline elements after the beam has been accelerated.
