http://hdl.handle.net/2104/5505 2013-05-25T12:59:59Z http://hdl.handle.net/2104/8563 Mode Couplings and Conversions for Horizontal Dust Particle Pairs in Complex Plasmas Qiao, Ke; Kong, Jie; Zhang, Zhuanhao; Matthews, Lorin; Hyde, Truell The normal modes for horizontal dust particle pairs in a complex plasma are investigated using two methods, a numerical calculation and a molecular dynamics simulation. The ion wakefield downstream of each particle and the variation of charge with particle levitation height are taken into account independently. It is shown that both mechanisms can create mode couplings or hybrid modes. As the modes hybridize, their frequencies are altered. Mode conversions and resonance instabilities are also observed and examined near the resonance points. The resulting power spectrum clearly resembles the experimentally observed high energy density signature for large crystals. The criteria for the occurrence of both the mode conversion and resonance instability are found to be accurately calculated by the double derivative of the interparticle potential, for both the ion wakefield and charge variation cases. 2013-04-01T00:00:00Z http://hdl.handle.net/2104/8562 Vertical Interaction Between Dust Particles Confined in a Glass Box in a Complex Plasma Kong, Jie; Qiao, Ke; Carmona-Reyes, Jorge; Douglass, Angela; Zhang, Zhuanhao; Matthews, Lorin; Hyde, Truell In this experiment, falling particle trajectories within and without a glass box placed on the lower electrode in a Gaseous Electronics Conference reference cell are recorded and analyzed, and the electrostatic forces exerted on the dust particles are measured and compared. Experimental results show that, for particles falling in a complex plasma with no glass box, only a single force balance point (i.e., the position where the gravitational force is balanced by the electrostatic force) exists in the vertical direction while, for particles falling inside a glass box, this force balance spans an extended vertical range. 2013-04-01T00:00:00Z http://hdl.handle.net/2104/8561 Glow and Dust in Plasma Boundaries Land, Victor; Douglass, Angela; Qiao, Ke; Zhang, Zhuanhao; Matthews, Lorin; Hyde, Truell W. The sheath region is probed in different complex plasma experiments using dust particles in addition to the measurement of the optical emission originating from the plasma. The local maximum in the optical emission coincides with the breaking of quasi-neutrality at the sheath boundary, as indicated by the vertical-force profile reconstructed from dust-particle trajectories as well as by the local onset of dust-density waves in high-density dust clouds suspended in a dielectric box. 2013-04-01T00:00:00Z http://hdl.handle.net/2104/8560 A New Inductively Driven Plasma Generator (IPG6)—Setup and Initial Experiments Dropmann, Michael; Herdrich, Georg; Laufer, Rene; Puckert, Dominik; Fulge, Hannes; Fasoulas, Stefanos; Schmoke, Jimmy; Cook, Mike; Hyde, Truell W. As part of the partnership between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University and the Institute of Space Systems (IRS) at the University of Stuttgart, a new design for a modular inductively driven plasma generator (IPG) is being developed and tested within CASPER and the IRS. The current IPG design is built on a well-established heritage of modular IPGs designed and operated at IRS. This latest IPG source enables the electrodeless generation of high-enthalpy plasmas and will provide CASPER researchers with the ability to operate with various gases at plasma powers of approximately 15 kW. It will also provide minimized field losses and operation over a wide scope of parameters not possible using existing designs requiring flow-controlled stabilization. The setup of the two facilities in Stuttgart (IPG6-S) and at Baylor (IPG6-B) is described, and results from the first characterization with air plasma are presented. Furthermore, the objectives of the test facilities will be described shortly. 2013-04-01T00:00:00Z