Comment on “Uniformization of the transverse beam profile by means of nonlinear focusing method”

This Comment presents unpublished and published work done by Los Alamos National Laboratory (LANL) in the period 1990 to 1999 using the nonlinear focusing method outlined in the recent publication by Yuri et al. [Phys. Rev. ST Accel. Beams 10, 104001 (2007)]. The LANL work included theory, design, modeling, and testing of nonlinear focusing beam “expanders” for use with high energy proton beams, including the proposed 1.7-GeV, 100-mA cw proton Accelerator for the Production of Tritium (APT). For several reasons listed in the text, the APT nonlinear focusing beam expander design was replaced with a high-frequency beam raster system.