Multicomponent simulation of plasma-sheath formation in presence of an emissive surface

In a wall-confined environment, the plasma behaviour can be identified by dividing the domain in two main regions: the bulk, where the quasi-neutrality prevails (the charge density is close to zero) and the sheath region near the walls, where positive space charge is built. This phenomenon is due to a higher mobility of electrons, creating an electric potential structure that accelerates the ions towards the surface and repels the electrons. In this work we present a multicomponent approach to the problem of the formation of sheath in the presence of a thermionic emissive surface: this type of materials are of particular interest in the modeling of emissive probes or in novel thermal protection systems strategies that include the use of electron transpiration cooling materials for hypersonic leading edges.