Generation and Propagation of an Intense Rotating Proton Beam

An annular magnetically insulated diode in a cusplike magnetic field has been used to produce an {~}6-kA, {~}190-kV rotating proton beam. Diamagnetic signals and magnetically insulated Faraday cups indicate that (35±{}15)% of the beam traversed the cusp and reached the end of the system magnetic field 35 cm from the diode. Diamagnetism was in excess of 2% of the 8-kG applied field, and the beam was distinctly hollow with a 6-cm average radius.