Abstract

This paper summarizes experiments that use magnetic fields to control the current in discharge tubes. In theory, the trajectory of electrons, in a magnetic field applied parallel to their initial direction of motion, describes a spiral path as these electrons follow the magnetic field lines. This results in an overall longer path with a higher probability of ionizing more gas molecules with a resulting increase in current (Yarwood 1945). In these experiments, the magnetic field was oriented parallel to the stream of electrons emitted from a cold cathode in a discharge tube. The experiments determined the magnetic field strength necessary to control tube current by lengthening the electron path.