HIDPL Articles
Permanent URI for this collectionhttps://hdl.handle.net/2104/5505
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Browsing HIDPL Articles by Author "Carmona-Reyes, Jorge"
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Item Agglomeration of Dust Particles in the Lab(AIP Conference Proceedings, 2011) Matthews, Lorin Swint.; Carmona-Reyes, Jorge; Land, Victor; Hyde, Truell Wayne.Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. The asymmetric charge on the aggregates causes them to rotate as they interact with the sheath electric field or other aggregates The charge and dipole moment can be estimated and compared to numerical models. “Dust molecules”, where two particles are electrostatically bound but not physically touching, are also observed.Item Crystallization Dynamics of a Single Layer Complex Plasma(Physical Review Letters, 2010-09) Hartmann, Peter; Douglass, Angela Michelle.; Carmona-Reyes, Jorge; Matthews, Lorin Swint.; Hyde, Truell Wayne.; Kovacs, Aniko Zs.; Donko, ZoltanWe report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time evolution of the recrystallization process following a rapid quench of a two-dimensional dust liquid. The experiments were accompanied by large-scale (million-particle) molecular dynamics simulations, assuming Yukawa-type interparticle interaction. Both experiment and simulation show a t ^/alpha (power-law) dependence of the linear crystallite domain size as measured by the bond-order correlation length, translational correlation length, dislocation (defect) density, and a direct size measurement algorithm. The results show two stages of order formation. On short time scales, individual particle motion dominates; this is a fast process characterized by alpha = 0.93 +/- 0.1. At longer time scales, small crystallites undergo collective rearrangement, merging into bigger ones, resulting in a smaller exponent /alpha = 0.38 +/- 0.06.Item Dust as probe for horizontal field distribution in low pressure gas discharges(Plasma Sources Science and Technology, 2014-06-23) Hartmann, Peter; Kovacs, Aniko Zs.; Carmona-Reyes, Jorge; Matthews, Lorin Swint.; Hyde, Truell Wayne.Using dust grains as probes in gas discharge plasma is a very promising, but at the same time very challenging method, as the individual external control of dust grains has to be solved. We propose and demonstrate the applicability of the RotoDust experiment, where the well controlled centrifugal force is balanced by the horizontal confinement field in plane electrode argon radio frequency gas discharges. We have reached a resolution of 0.1 V cm−1 for the electric field. This technique is used to verify numerical simulations and to map symmetry properties of the confinement in dusty plasma experiments using a glass box.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 Measurement of net electric charge and dipole moment of dust aggregates in a complex plasma(Physical Review E, 2014-09-02) Yousefi, Raziyeh.; Davis, Allen; Carmona-Reyes, Jorge; Matthews, Lorin Swint.; Hyde, Truell Wayne.Understanding the agglomeration of dust particles in complex plasmas requires knowledge of basic properties such as the net electrostatic charge and dipole moment of the dust. In this study, dust aggregates are formed from gold-coated mono-disperse spherical melamine-formaldehyde monomers in a radiofrequency (rf) argon discharge plasma. The behavior of observed dust aggregates is analyzed both by studying the particle trajectories and by employing computer models examining three-dimensional structures of aggregates and their interactions and rotations as induced by torques arising from their dipole moments. These allow the basic characteristics of the dust aggregates, such as the electrostatic charge and dipole moment, as well as the external electric field, to be determined. It is shown that the experimental results support the predicted values from computer models for aggregates in these environments.Item Mode coupling and resonance instabilities in quasi-two-dimensional dust clusters in complex plasmas(American Physical Society, 2014-09-16) Qiao, Ke; Kong, Jie; Carmona-Reyes, Jorge; Matthews, Lorin Swint.; Hyde, Truell Wayne.Small quasi-two-dimensional dust clusters consisting of three to eleven particles are formed in an argon plasma under varying rf power. Their normal modes are investigated through their mode spectra obtained from tracking the particles’ thermal motion. Detailed coupling patterns between their horizontal and vertical modes are detected for particle numbers up to 7 and discrete instabilities are found for dust clusters with particle number 9, as predicted in previous theory on ion-flow induced mode coupling in small clusters. The instabilities are proven to be induced by resonance between coupled horizontal and vertical normal modes.Item Slow Plastic Deformation (Creep) of 2D Dusty Plasma Solids(Physical Review Letters, 2014-07-09) Hartmann, Peter; Kovacs, Aniko Zs.; Douglass, Angela Michelle.; Carmona-Reyes, Jorge; Matthews, Lorin Swint.; Hyde, Truell Wayne.We report complex plasma experiments, assisted by numerical simulations, providing an alternative qualitative link between the macroscopic response of polycrystalline solid matter to small shearing forces and the possible underlying microscopic processes. In the stationary creep regime we have determined the exponents of the shear rate dependence of the shear stress and defect density, being α=1.15±0.1 and β=2.4±0.4, respectively. We show that the formation and rapid glide motion of dislocation pairs in the lattice are dominant processesItem Vertical Interaction Between Dust Particles Confined in a Glass Box in a Complex Plasma(IEEE Transactions on Plasma Science, 2013-04) Kong, Jie; Qiao, Ke; Carmona-Reyes, Jorge; Douglass, Angela Michelle.; Zhang, Zhuanhao.; Matthews, Lorin Swint.; Hyde, Truell Wayne.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.