On the formation of high-voltage double layers in a collisionless plasma column

Abstract

It was made attempt to derive conditions for double layer (DL) formation in collisionless plasma by means of spectral method. Homogeneous plasma carrying a constant current is considered using the system of equations consisting of continuity equation, momentum balance equation for electrons and ions and Poissn’s equation. Linearizing considered system and implying local electric field splash caused by DL it was presumed the wide Fourier spectrum. Number of conditions for DL existence was derived. It was obtained quasi-neutrality condition, Langmuir condition and generalized Bohm condition. These results are interpreted comparing with triple plasma device experiments. For DL formation energies and number densities of charged particles penetrating into the chamber should correlate with the potential drop between the plasma sources and electric field according to the generalized Bohm criterion.