The planar continuum plasma sheath with regeneration and convection of ionization

Abstract

Measurements are described on a planar sheath established in a moving flame plasma seeded with potassium. By varying the quantity of seed the ionization density of the flame is altered so as to allow a range of sheath current-voltage characteristics which vary from saturation at low densities to a substantial voltage dependence at high densities. When the sheath is suddenly collapsed the ionization within what was the sheath region is observed to recover towards its equilibrium value. Measurements of current density, ionization density, and sheath thickness taken during these experiments show good agreement with a sheath model in which convection and/or ionization regeneration act as the supply of ions to the sheath.