Determining Forces On Dust Grains In A Plasma With A Position-Dependent Number Density

Complex plasma environments can give insight into the nature of systems that do not obey Newton’s third law. As negatively charged dust particles interact with flowing ions, the ion wake-field forms a positively charged spatial region. The force from the wake-field is non-reciprocal in nature, as only a downstream particle is influenced by the wake. This wake-field interaction gives insight into the conditions and forces needed to create stable dust structures. A molecular dynamics simulation of flowing ions and dust grain is used to model vertically oriented dust chains that have been confined by a glass box placed on the lower electrode in a Gaseous Electronics Conference rf cell to gain insight into the forces acting on these particles. Previous simulations of this structure employing a constant ion number density indicated that the sheath electric field and dust charge is not constant. This model has been extended to include the effect of the ion number density decreasing towards the lower electrode and the effect of multiple chains. This simulation is applied iteratively, minimizing the force balance equation to give insight into the conditions needed for stability.