Magnetic insulation of an intense relativistic electron beam

Abstract

A magnetic field is used as an insulator, preventing electrons from crossing the gap of a pulsed field‐emission diode subjected to voltages of 100–250 kV. The diode is comprised of two concentric cylinders with a variable gap separation ranging from 2 to 6 mm. A pulsed magnetic field up to 15 kG is applied along the diode axis. When the magnetic field exceeds a certain critical value, the electron current (which is typically 10–30 kA) is reduced by approximately two orders of magnitude. The desired magnetic insulation lasts over the full 50‐nsec voltage pulse.