Dust pattern formation in unmagnetized and weakly-magnetized low temperature plasmas*

Previous experiments conducted in the Magnetized Dusty Plasma eXperiment (MDPX) have revealed many novel phenomena, one of which is the formation of imposed, ordered structures in a strongly magnetized dusty plasma (B > 1 T). It was shown that microparticles in a strongly magnetized capacitively coupled RF plasma align themselves according to the gridded pattern of a conducting wire mesh placed above the dust layer (T. Hall et al. Phys. Plasmas 25, 103702 (2018)). The roles of the magnetic field, neutral pressure, plasma density, and the structure of the wire mesh were investigated to characterize their influence on the imposed structures. The goal of this new work is to understand the dust patterns and the electric potential structures during the transition from an unmagnetized to a strongly magnetized plasma. Preliminary experiments seek to characterize the bond order parameter of dust layers in plasmas with varying pressures and RF power. The behavior of a dust layer with and without a mesh above it is studied in unmagnetized and weakly magnetized plasmas in a tabletop setup as preparation for studying strongly magnetized dusty plasmas in the MDPX device.