Injection and control of intense relativistic electron beams in a torus

Efficient injection (>80%) of an intense relativistic electron beam into a torus has been achieved using curvature drift injection. Drift was stabilized with a supplemental dipole magnetic field but beam loss in the radial direction due to the defocusing effect of the dipole field limited containment time. We propose a system for beam trapping and confinement which employs drift injection and beam energy losses in a toroidal-plus-betatron-type field.