The structure of the convection sustained ion sheath

Abstract

The detailed structure of the convection sustained ion sheath has been examined. With Re = vfL/μikTe/e (the electric Reynolds number) and α = (ε0kTe/nee2)1/2(1/L), where vf = plasma flow velocity, μi = ion mobility, k = Boltzmann's constant, Te = electron temperature, e = electron charge, ε0 = permittivity of free space, ne = electron density, and L = characteristic length, it is found that for [Formula: see text], no 'presheath' or diminution of electron density outside the sheath is evident, whereas for [Formula: see text], a very substantial density gradient exists which is in fact similar to the quasi-neutral region which occurs in stationary plasmas. Calculations are presented which enable ion and electron densities and electric field and potential to be calculated through the presheath and sheath regions.