Image current guiding of a relativistic electron beam in a foil focusing system

Intense relativistic electron beams can be focused by arrays of transverse conducting foils or meshes. The meshes cancel beam-generated radial electric fields, allowing a self-pinched equilibrium. The experiments reported confirm that foil focusing systems can also steer high-current beams. We applied a dipole perturbation field to deflect a 3.8 kA, 280 keV beam in a foil array. We found that image current forces centered the beam in the transport pipe. The measured deflection was more than an order of magnitude smaller than the predicted value for single electron orbits. The results show that foil focusing may have application to recirculating accelerators for high-current electron beams