Novel method of charging an accumulator ring

For high power fusion applications, a circular accelerator for heavy ions is not likely to be competitive with a linear accelerator. This is principally because one requires rather high accelerator efficiencies, and quite large average power. Efficiencies greater than or equal to 10 percent, and perhaps 30 and 50 MW of average beam power are needed. On the other hand, the linear accelerator can be built to satisfy these constraints, and in addition, it is ideally suited for multi-turn injection. A difficulty with multi-turn injection is that in typical application it is rather lossy. With care, and sufficient phase space dilution, one might hope to obtain greater than or equal to 90 percent injection efficiency, but even at these levels the large amount of beam power lost in the accumulator might have serious consequences for the machine operation. Therefore, it is desirable to be able to use ''box car'' stacking, which is essentially 100 percent without particle loss. A method of operating the linear accelerator so that the output beam is of suitable instantaneous current to permit box-car stacking with the linac output is proposed