Contraction of gas discharge luminosity at low pressures and low currents

摘要

The problem of the excited atom radial profile formation in a positive column is of an importance for gas light sources. It is well known that contraction of the positive column of an inert gas discharge at pressures of tens and hundreds of Torr takes place. At not high pressures a discharge luminosity is constricted towards the axis of the discharge tube. At higher pressures an abrupt contraction of the discharge occurs. At low pressures and small currents the radial profiles of the discharge intensity and electron density are usually supposed to be besselian. This assumption follows from the traditional theories based on the local kinetics of electrons, such as Langmuir-Tonks theory for the free-flight regime or Shottky theory for the diffusive ease of charged particle losses.