Equilibrium of a high-current electron ring in a modified-betatron accelerator

Abstract

The dynamics of an ultrahigh-current electron ring in a modified-betatron configuration is addressed. This study includes analytical and numerical results for both ‘‘cold’’ and ‘‘hot’’ rings. It has been found that the walls surrounding the ring and toroidal effects play a very important role in the dynamics of the ring, even when the wall conductivity is infinite. For finite wall conductivity, the diffusion of the ring’s self-magnetic field profoundly impacts its dynamics and in general the equilibrium could be lost if means are not provided to compensate for this effect. In addition, it has been found that the toroidal-field grad B drift is not important, except when the bounce frequency is very small. The general conclusion of these studies is that equilibrium states of ultrahigh-current rings in modified-betatron configuration exist over a wide range of parameters. These states are accessible and within the reach of existing pulsed power technology.