Field error resonances in the NRL modified betatron accelerator

Summary form only given. Static field error resonances may have a disrupting effect on the beam dynamics in the modified betatron accelerator (MBA) under development at the US Naval Research Laboratory (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: (i) the finite number of discrete coils generating the toroidal field, resulting in a bumpy toroidal field, and (ii) the distortion of the induced current (induced by the time-varying vertical field) due to the presence of input and/or diagnostic ports in the resistive toroidal chamber. Analysis of the particle orbit equations indicates that the field errors associated with the ports and the discrete toroidal coils may be the cause of current loss in the NRL MBA. These field errors may be reduced by introducing corrective coils