Space-Charge and Fringe-Field Effects in Simulations of Non-Scaling FFAGs

Recent simulations of non-scaling fixed-field alternating gradient accelerators (FFAGs) suggest that magnet fringe-field effects are of signal importance. In addition, non-scaling FFAGs are sensitive to a slew of resonances during the acceleration ramp. We present simulations of possible non-scaling FFAG designs, focusing especially on the effects fringe-fields and space-charge, using newly developed capabilities in the code PTC% \footnote{E. Forest, Y. Nogiwa, F. Schmidt, ``The FPP and PTC Libraries'', Proc. ICAP'2006.}. In particular, we study how fringe extent and other parameters affect important measures of machine performance. An important consideration---because it affects the amount of rf power required---will be the speed at which resonances must be crossed.