Kinetic theory and simulations of moderately strong stationary double layers with warm ions

Summary form only given. In this paper we present results obtained via kinetic theory and simulation on double layer structures (DLs) joining separating two non-isothermal plasmas with different ion and electron temperatures and densities such that DL´s potential barrier strengths range from rather low to “infinite” (in comparison to particle thermal energies) in either of plasmas. This strongly non-linear problem, which consists of solving the so-called force balance equation subject to four boundary conditions (quasineutralities and generalized Bohm criteria), has been already solved self-consistently in fluid approach resulting in a modified form of Langmuir criterion, which however, suffers of a singularity for moderately strong double layers. In addition, boundary conditions have been imposed as free parameters of the problem instead of being calculated self-consistently, as done, e.g., in Ref. 3, for particular ionization rate distributions (proportional to electron density). For possible taking the same approach as in Ref. 3, i.e., to obtain a controllable DL with inhomogeneous ionization distributions, as an integral part of the discharge, and finding the double layer conditions (instead of imposing them in advance), here we obtain enough “experimental” observations and compile data from kinetic simulations, performed with our branch of a 1D PIC PTSG code. Thus the only free parameters that remain in maintaining a DL with desired strenght, are only those which all are contained within the ion-source term distribution, i.e., the external discharge parameters to be controlled by an experimentalist.