Role of aberrations in high-current plasma lenses

The influence of spherical and momentum aberrations on the focusing characteristics of intense ion beams in the electrostatic plasma lens (PL) is analyzed. The dependence of the ion beam focus on the uncompensated beam space charge and the finite azimuthal velocity at the PL exit is examined. Minimum focused beam radii are calculated for different system parameters and are shown to depend on the ion charge-to-mass ratio. The radial profiles of focused, multicharged, inhomogeneous ion beams were measured experimentally and compared with the theoretical predictions. We show that the PL, in principle, can be used for ion charge state analysis.