Abstract:

This work studies with a Langmuir probe axial profiles of such plasma parameters as electron temperature, plasma potential and concentration of the direct current glow discharge in nitrogen for various gas pressure values. The electric field strength is shown to be small in the negative glow whereas axial profiles of plasma concentration and electron temperature possess maxima. These parameters approach their minima near the interface separating the negative glow and the dark Faraday space. The strata are observed in the positive column at low gas pressure whereas at higher pressure (above 0.5 Torr) the column becomes uniform. The axial profile of plasma concentration in the dark Faraday space is found to attain a maximum that may exceed the average plasma concentration in the positive column. Increased ionization in the dark Faraday space may be caused by a step-like ionization of metastable nitrogen molecules by electrons having acquired the sufficient energy in the increasing electric field. It is expedient not to relate the dark Faraday space to cathode parts of the glow discharge but regard this space as a starting (preliminary) form of the positive column.

Keywords: