Nonlinear dynamics in dusty plasmas subjected to photo-discharging

Experiments on the DPX apparatus at Auburn University, indicate that LaB6 microparticles suspended in a low-temperature argon plasma can be photoelectrically discharged by a high-intensity UV source. Different particles in the experiment exhibited more periodic or chaotic responses to the discharge. In order to better understand the hypothesized role that particle shape may play in determining this behavior, a campaign of simulated discharges of ellipsoidal dust particles was generated. These simulations indicate that when the discharge is presumed to be proportional to the area which the particle projects along the axis illuminated by the discharging UV source, then more spherical particles trend towards periodic behavior, while more elongated or flattened particles trend towards chaotic behavior. Examples of simulated behavior in real and phase space are presented and an analysis of the relationship between particle symmetry and the dynamics resulting from photo-discharge are discussed.