Examining Ionization Wave Effects on Self-Organization of Dust Chains

The PlasmaKristall-4 (PK-4) experiment on the International Space Station (ISS) has been widely used to study collective behavior and self-organization of dust grains immersed in a plasma environment under microgravity conditions. Recently it has been shown that the PK-4 BU, a ground-based replica of the PK-4, supports the presence of inhomogeneous features related to ionization waves moving through the positive column on the microsecond timescale 1 . Plasma conditions within the ionization waves, such as plasma density and electric fields, have been shown to vary by up to an order of magnitude from background values. Previous investigations of dust dynamics within the PK-4 environment have focused on time-averaged plasma conditions, assuming a homogeneous environment. Given the importance of plasma density and electric fields for dust self-organization, it is important to understand the impact of their observed variability. Here results will be presented from an N-body simulation which models dust and ion dynamics, employing initial boundary conditions derived from a 2D particle-in-cell with Monte Carlo collisions (PIC/MCC) simulation of the observed ionization waves.