Particles as probes for complex plasmas in front of biased surfaces

TL;DR

This paper explores how micro-particles can be used as diagnostic probes to measure electric fields in complex plasmas near biased surfaces, combining experimental and numerical methods.

Contribution

It introduces experimental and numerical analysis of particle behaviour in front of biased surfaces, enhancing understanding of plasma-particle interactions for diagnostics.

Findings

Particles can serve as electrostatic probes for local electric fields.

Particle behaviour depends on bias conditions and plasma parameters.

Numerical simulations complement experimental observations.

Abstract

An interesting aspect in the research of complex (dusty) plasmas is the experimental study of the interaction of micro-particles with the surrounding plasma for diagnostic purposes. Local electric fields can be determined from the behaviour of particles in the plasma, e.g. particles may serve as electrostatic probes. Since in many cases of applications in plasma technology it is of great interest to describe the electric field conditions in front of floating or biased surfaces, the confinement and behaviour of test particles is studied in front of floating walls inserted into a plasma as well as in front of additionally biased surfaces. For the latter case, the behaviour of particles in front of an adaptive electrode, which allows for an efficient confinement and manipulation of the grains, has been experimentally studied in dependence on the discharge parameters and on different bias conditions of the electrode. The effect of the partially biased surface (dc, rf) on the charged micro-particles has been investigated by particle falling experiments. In addition to the experiments we also investigate the particle behaviour numerically by molecular dynamics, in combination with a fluid and particle-in-cell description of the plasma.