Injection of Intense Relativistic Electron Beams into a Toroidal Geometry

Two experimentally verified methods are presented for the injection of high-current relativistic electron beams (30 kA, 400 kV) into strong toroidal magnetic fields (1-8 kGauss). Injection is accomplished by contouring the current flow in the stalk of a field-emission cathode to perturb the flux lines only during beam generation. On conclusion of the emission process the perturbed lines can return to their original positions thereby trapping the beam.