title: Vertical-probe-induced asymmetric dust oscillation in complex plasma.
abstract: A complex plasma vertical oscillation experiment which modifies the bulk is presented. Spherical, micron-sized particles within a Coulomb crystal levitated in the sheath above the powered lower electrode in a GEC reference cell are perturbed using a probe attached to a Zyvex S100 Nanomanipulator. By oscillating the probe potential sinusoidally, particle motion is found to be asymmetric, exhibiting superharmonic response in one case. Using a simple electric field model for the plasma sheath, including a nonzero electric field at the sheath edge, dust particle charges are found by employing a balance of relevant forces and emission analysis. Adjusting the parameters of the electric field model allowed the change predicted in the levitation height to be compared with experiment. A discrete oscillator Green's function is applied using the derived force, which accurately predicts the particle's motion and allows the determination of the electric field at the sheath edge.
authors.affiliation: CASPER (Center for Astrophysics, Space Physics, and Engineering Research), Baylor University, Waco, Texas 76798-7310, USA. brandon_harris@baylor.edu
authors.forename: B J
authors.initials: BJ
authors.lastname: Harris
authors.forename: L S
authors.initials: LS
authors.lastname: Matthews
authors.forename: T W
authors.initials: TW
authors.lastname: Hyde
mesh_terms: D003198:Computer Simulation; D004391:Dust / Q000032:analysis*; D008956:Models, Chemical; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D009991:Oscillometry / Q000379:methods*; D010316:Particle Size; D058626:Plasma Gases / Q000737:chemistry*
chemical_list: D004391:Dust; D058626:Plasma Gases