LETTERS TO THE EDITOR: Spectroscopic evidence of deviation from Maxwell's law of electron velocities in the helium positive column

Abstract

The measured luminous-flux ratio of the singlet and triplet lines at 5048 and 4713 A is constant close to and on the axis of the discharge tube, but increases towards the tube wall. Analysis shows that an electron-velocity distribution function of exponential form for the region near the tube wall is not compatible with this observation.