Field error resonances in the NRL modified betatron accelerator

Static field error resonances may have a disrupting effect on the beam dynamics in the modified betatron accelerator (MBA) under development at NRL. These field error resonances are expected to occur when the ratio of the toroidal field to the time varying vertical field is approximately equal to an integer. There are a number of potential sources for the field errors in the MBA. These include: the finite number of discrete coils generating the toroidal field (twelve in the NRL MBA), resulting in a bumpy toroidal field and the distortion of the induced current (induced by the time varying Bz field) due to the presence of input and/or diagnostic ports in the resistive toroidal chamber