Abstract: | The purpose of this talk is to mathematically discuss the formation of a plasma sheath near the surface of materials immersed in a plasma, and to study qualitative information of such a plasma sheath layer. Specifically, we study the quasi-neutral limit of solutions to the Euler-Poisson system in a half space and annular domain by establishing $L^2$ and $H^1$ estimates of the difference between the solutions to the Euler-Poisson system and its quasi-neutral limiting system, incorporated with the correctors for the boundary layers. The pointwise estimate of correctors enables us to obtain the thickness of boundary layers. |