Hypervelocity Impacts and Dusty Plasma Lab (HIDPL)
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Browsing Hypervelocity Impacts and Dusty Plasma Lab (HIDPL) by Author "Cook, Mike"
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Item Dusty Plasma Correlation Function Experiment(Advances in Space Research, 2004) Smith, Bernard (Bernie).; Vasut, John; Matthews, Lorin Swint.; Hyde, Truell Wayne.; Reay, Jerry; Cook, Mike; Schmoke, JimmyDust particles immersed within a plasma environment, such as those in protostellar clouds, planetary rings or cometary environments, will acquire an electric charge. If the ratio of the inter-particle potential energy to the average kinetic energy is high enough the particles will form either a “liquid” structure with short-range ordering or a crystalline structure with long range ordering. Many experiments have been conducted over the past several years on such colloidal plasmas to discover the nature of the crystals formed, but more work is needed to fully understand these complex colloidal systems. Most previous experiments have employed monodisperse spheres to form Coulomb crystals. However, in nature (as well as in most plasma processing environments) the distribution of particle sizes is more randomized and disperse. This paper reports experiments which were carried out in a GEC radio frequency reference cell modified for use as a dusty plasma system, using varying sizes of particles to determine the manner in which the correlation function depends upon the overall dust grain size distribution. (The correlation function determines the overall crystalline structure of the lattice.) Two-dimensional plasma crystals were formed of assorted glass spheres with specific size distributions in an argon plasma. Using various optical techniques, the pair correlation function was determined and compared to those calculated numerically.Item The effect of electrode heating on the discharge parameters in complex plasma experiments(IOP Publishing, 2011-01-25) Land, Victor; Carmona-Reyes, Jorge; Creel, James Ruell.; Schmoke, Jimmy; Cook, Mike; Matthews, Lorin Swint.; Hyde, Truell Wayne.Thermophoresis is a tool often applied in complex plasma experiments. One of the usual stated benefits over other experimental tools is that electrode temperature changes required to induce thermophoresis do not directly influence the plasma parameters. From electronic data, plasma emission profiles in the sheath, and Langmuir probe data in the plasma bulk, we conclude that this assumption does not hold. An important effect on the levitation of dust particles in argon plasma is observed as well. The reason behind the changes in plasma parameters seems to be the change in neutral atom density accompanying the increased gas temperature while running at constant pressure.Item A New Inductively Driven Plasma Generator (IPG6)—Setup and Initial Experiments(IEEE Transactions on Plasma Science, 2013-04) Dropmann, Michael; Herdrich, Georg; Laufer, Rene; Puckert, Dominik; Fulge, Hannes; Fasoulas, Stefanos; Schmoke, Jimmy; Cook, Mike; Hyde, Truell Wayne.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.Item Phase Transitions in a Dusty Plasma with Two Distinct Particle Sizes(Advances in Space Research, 2008) Smith, Bernard (Bernie).; Hyde, Truell Wayne.; Matthews, Lorin Swint.; Reay, Jerry; Cook, Mike; Schmoke, JimmyIn semiconductor manufacturing, contamination due to particulates significantly decreases the yield and quality of device fabrication, therefore increasing the cost of production. Dust particle clouds can be found in almost all plasma processing environments including both plasma etching devices and in plasma deposition processes. Dust particles suspended within such plasmas will acquire an electric charge from collisions with electrons and ions in the plasma. If the ratio of inter-particle potential energy to the average kinetic energy is sufficient, the particles will form either a “liquid” structure with short-range ordering or a crystalline structure with long-range ordering. Many experiments have been conducted over the past decade on such colloidal plasmas to discover the character of the systems formed, but more work is needed to fully understand these structures. The preponderance of previous experiments used monodisperse spheres to form complex plasma systems. However, most plasma processing environments contain more arbitrary distributions of particle size. In order to examine in more detail the effects of a size distribution, experiments were carried out in a GEC rf reference cell modified for use as a dusty plasma system. Using two monodisperse particle sizes, experiments were conducted to determine the manner in which phase transitions and other thermodynamic properties depended upon the overall dust grain size distribution. Plasma crystals were formed from different mixtures of 8.89 and 6.50 μm monodisperse particles in argon plasma. With the use of various optical techniques, the pair correlation function was determined at different pressures and powers and then compared to measurements obtained for monodisperse spheres.