Plasma Sheath Structures in Complex Electrode Geometries

Abstract

The behavior of microparticles trapped in the curved plasma sheath in the corner of a horizontal rf electrode and a vertical wall is investigated by experiments and simulation. Three types of walls are studied, namely a dielectric wall, a floating conductive wall, and a conductive wall at the same potential as the rf electrode. The particle's equilibrium position provides insight in the acting forces, associated potentials and field structures. Complementary particle-in-cell simulations elucidate the structure of the charged-species densities and electric potential profile throughout the sheath. Thereby special emphasis is placed on how the sheath structure in the corner depends on the wall material.

Wall Charge and Potential from a Microscopic Point of View

“…The reaction chain (8) consists of two sequential resonant tunneling processes (see Fig. The Hamiltonian appropriate for (8) reads Each step can be modelled by an Anderson-Newns Hamiltonian [35], which is an effective model, stripped of some of the microscopic details and characterized instead by a small number of material parameters which can be easily obtained.…”

“…Models of this type are well suited for describing elementary processes at plasma walls where the lack of surface diagnostics prevents a more refined modeling. The Hamiltonian appropriate for (8) reads…”

“…How electrons are trapped in or at the wall, what their binding energy and residence time is, how and from what kind of electronic states they are released, and how the sheath potential merges with the surface potential of the wall are beyond the scope of this crude modeling of the plasma wall. In dusty plasmas [4][5][6][7][8], for instance, the total amount of charge soaked up by the dust particles affects of course the overall characteristic of the discharge [9] and should thus be known as precisely as possible. In dusty plasmas [4][5][6][7][8], for instance, the total amount of charge soaked up by the dust particles affects of course the overall characteristic of the discharge [9] and should thus be known as precisely as possible.…”

“…In various novel bounded plasmas [3] it seems to be however rewarding to pay more attention to these questions. In dusty plasmas [4][5][6][7][8], for instance, the total amount of charge soaked up by the dust particles affects of course the overall characteristic of the discharge [9] and should thus be known as precisely as possible. Likewise it is by now also well known [10][11][12][13][14] that the wall charge plays an active role in determining the spatio-temporal structure of dielectric barrier discharges [15] and microplasmas [16,17].…”

Recent Progress in Complex Plasmas

“…In the first article, Schubert et al [7] study the behaviour of microparticles trapped in the curved plasma sheath of a complex electrode geometry by experiment and PIC-MCC simulations. In the first article, Schubert et al [7] study the behaviour of microparticles trapped in the curved plasma sheath of a complex electrode geometry by experiment and PIC-MCC simulations.…”