Improvements on the HIBALL Heavy Ion Fusion Driver

Preliminary studies of accelerator scenarios suitable for the HIBALL Heavy Ion Fusion Reactor Study have shown that it is of interest to consider an RF linac beam current as high as possible in order to reduce the filling time of the storage rings to about 1 msec. It is shown here for singly charged Bi ions (10 GeV kinetic, 5 MJ total energy) that such a scenario helps to avoid growth of the resistive microwave mode and reduces the complexity of transverse stacking manipulations in the rings. This work indicates that it might be desirable for future studies to lower the linac current and thus the enormous instantaneous RF power consumption by finding ways to suppress microwave growth in order to stretch the storage ring filling time.