Jorge Carmona | Baylor University (original) (raw)

Papers by Jorge Carmona

Bulletin of the American Physical Society, 2017

arXiv: Plasma Physics, 2020

Ion wake induced mode coupling is investigated experimentally for a horizontal dust chain formed ... more Ion wake induced mode coupling is investigated experimentally for a horizontal dust chain formed in a complex plasma, verifying results from previous simulation. A double branch of faint spectral lines is detected in the mode spectra which verifies the predicted rule of mode coupling between the vertical z(j=i$\pm$1) modes and the longitudinal mode x(i). Discreet instabilities are observed as the branches of x- and z-modes intersect each other. The mode spectra in the vicinity of the instabilities exhibit enhanced energy density at specific coupled x and z modes, serving as direct evidence that these instabilities are caused by resonance between the coupled modes. The instability-induced melting threshold was found to obey the Lindemann criterion through analysis of the instantaneous relative interparticle distance fluctuation (IDF). The relation between mode spectra and dispersion relations was further studied by multiplying the mode spectra with a transition matrix connecting the ...

into the micro-excitations of dust in vertical chain bundles has recently increased due to intere... more into the micro-excitations of dust in vertical chain bundles has recently increased due to interest in the generic micro-behaviors of other 2+1 D liquids sharing similar characteristics. This is particularly true for systems providing external field alignment (for example, due to the ion wakefield) of the chain bundle. Most such chain motion is created due to (a) strong vertical interparticle coupling creating particle alignment within the chain, (b) topological constraints arising from the structure of the confinement which can "cage" the motion of the particle, and (c) thermal perturbations and/or local strain-induced stresses which can induce particle hopping and overall chain motion. This paper will discuss the third of these, i.e., the manner in which thermal perturbations and/or local strain-induced stresses can induce particle hopping and overall chain motion. Using a glass box placed on the lower powered electrode of a GEC rf reference cell to provide strong horizontal confinement, a vertical dust chain will be perturbed employing a diode pumped solid state laser (Coherent VERDI). The resulting particle hopping and overall chain motion will be examined theoretically and the manner in which the vertical interparticle force and the overall confinement impacts the underlying physics will be discussed.

2007 IEEE Pulsed Power Plasma Science Conference, 2007

Physical Review Letters, 2010

We report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time... more We report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time evolution of the re-crystallisation 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 inter-particle interaction. Both experiment and simulation show a ∝ t α (power law) dependence of the linear crystallite domain size as measured by the bondorder correlation length, translational correlation length, dislocation (defect) density, and a direct size measurement algorithm. The results show two stages of order formation: on short timescales individual particle motion dominates; this is a fast process characterized by α = 0.93 ± 0.1. At longer timescales , small crystallites undergo collective rearrangement, merging into bigger ones, resulting in a smaller exponent α = 0.38 ± 0.06.

IEEE Transactions on Plasma Science, 2009

University-Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelera... more University-Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. Interactions between pairs of aggregates allow their charge, mass, and gas drag to be inferred. The asymmetric charge on the aggregates causes them to rotate as they interact with each other. Through these interactions, the charge and dipole moment can be estimated and compared to numerical models.

Dust aggregates in complex plasmas have been studied theoretically in computer models, but not ex... more Dust aggregates in complex plasmas have been studied theoretically in computer models, but not extensively in an experimental setting. This work investigates several properties of aggregates which are responsible for dust dynamics: charge, dipole moment, and gas drag. A diode pumped laser is used to perturb aggregates in a GEC rf reference cell, and a high-speed camera acquires image data. Particle trajectories are extracted and analyzed to characterize or estimate values of the properties under investigation.

Plasma Sources Science and Technology, 2011

arXiv: General Physics, 2004

The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed constr... more The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed construction and calibration of a Light Gas Gun (LGG), which is used for low velocity impact studies. At geosynchronous orbit, space debris can impact commercial satellites at velocities of 500 m/s [1] reducing their useful lifetime. Additionally, there is an ever-increasing population of abandoned nonoperational satellites and related debris in these orbits [2]. Therefore, it is important to clearly understand the physics behind how such collisions can cause structural damage. This is most easily determined by measuring the damage incurred on representative material exposed to test collisions in the laboratory. Data collected in this manner will not only help illuminate the shock physics involved but can also aid in providing methods for designing advanced shielding for satellites.

Bulletin of the American Physical Society, 2019

Complex plasma containing conducting grains is common across a number of research environments. I... more Complex plasma containing conducting grains is common across a number of research environments. In space such plasmas can be formed from dust left over after the formation of stellar and protoplanetary systems where iron rich meteors, containing remnants of ...

Smith, J. York , R. Moore, M. Clyat, T. Buchs, R. Laufer, S. Attai, L. Matthews and T. W. Hyde, C... more Smith, J. York , R. Moore, M. Clyat, T. Buchs, R. Laufer, S. Attai, L. Matthews and T. W. Hyde, Center for Astrophysics, Space Physics, & Engineering Research, Baylor University, (Baylor University, Waco, Texas 76798, USA-Truell_Hyde@baylor.edu) , Educational Service Center Region 12 (2101 W Loop 340, Waco, TX 76712), Baylor School of Education (One Bear Place #97304,Waco, TX 76798-7304). La Vega Independent School District (555 TX-340 Loop, Waco, TX 76705),

A one stage Light Gas Gun (LGG) at CASPER [1] was employed to test the shielding capabilities of ... more A one stage Light Gas Gun (LGG) at CASPER [1] was employed to test the shielding capabilities of tiles composed of four different laminated nanotube combinations. These target tiles were named CSNEAT1, CSCNT1, HYCNTUT1 and HYCNTT1. For calibration purposes, a 3003- aluminum plate was also impacted and the craters formed on the various composition tiles compared.

2007 IEEE Pulsed Power Plasma Science Conference, 2007

ABSTRACT

Wakefield oscillations created by the ion wakefield existing below a dust particle within the pla... more Wakefield oscillations created by the ion wakefield existing below a dust particle within the plasma sheath generated above a powered lower electrode in a GEC rf reference cell carry information about the plasma sheath, the dust particle charge and the speed of the streaming ions. An experimental method to investigate such wakefield oscillations is discussed.

Plasma Sources Science and Technology, 2014

Using dust grains as probes in gas discharge plasma is a very promising, but at the same time ver... more 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 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.

Bulletin of the American Physical Society, 2017

arXiv: Plasma Physics, 2020

Ion wake induced mode coupling is investigated experimentally for a horizontal dust chain formed ... more Ion wake induced mode coupling is investigated experimentally for a horizontal dust chain formed in a complex plasma, verifying results from previous simulation. A double branch of faint spectral lines is detected in the mode spectra which verifies the predicted rule of mode coupling between the vertical z(j=i$\pm$1) modes and the longitudinal mode x(i). Discreet instabilities are observed as the branches of x- and z-modes intersect each other. The mode spectra in the vicinity of the instabilities exhibit enhanced energy density at specific coupled x and z modes, serving as direct evidence that these instabilities are caused by resonance between the coupled modes. The instability-induced melting threshold was found to obey the Lindemann criterion through analysis of the instantaneous relative interparticle distance fluctuation (IDF). The relation between mode spectra and dispersion relations was further studied by multiplying the mode spectra with a transition matrix connecting the ...

into the micro-excitations of dust in vertical chain bundles has recently increased due to intere... more into the micro-excitations of dust in vertical chain bundles has recently increased due to interest in the generic micro-behaviors of other 2+1 D liquids sharing similar characteristics. This is particularly true for systems providing external field alignment (for example, due to the ion wakefield) of the chain bundle. Most such chain motion is created due to (a) strong vertical interparticle coupling creating particle alignment within the chain, (b) topological constraints arising from the structure of the confinement which can "cage" the motion of the particle, and (c) thermal perturbations and/or local strain-induced stresses which can induce particle hopping and overall chain motion. This paper will discuss the third of these, i.e., the manner in which thermal perturbations and/or local strain-induced stresses can induce particle hopping and overall chain motion. Using a glass box placed on the lower powered electrode of a GEC rf reference cell to provide strong horizontal confinement, a vertical dust chain will be perturbed employing a diode pumped solid state laser (Coherent VERDI). The resulting particle hopping and overall chain motion will be examined theoretically and the manner in which the vertical interparticle force and the overall confinement impacts the underlying physics will be discussed.

2007 IEEE Pulsed Power Plasma Science Conference, 2007

Physical Review Letters, 2010

We report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time... more We report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time evolution of the re-crystallisation 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 inter-particle interaction. Both experiment and simulation show a ∝ t α (power law) dependence of the linear crystallite domain size as measured by the bondorder correlation length, translational correlation length, dislocation (defect) density, and a direct size measurement algorithm. The results show two stages of order formation: on short timescales individual particle motion dominates; this is a fast process characterized by α = 0.93 ± 0.1. At longer timescales , small crystallites undergo collective rearrangement, merging into bigger ones, resulting in a smaller exponent α = 0.38 ± 0.06.

IEEE Transactions on Plasma Science, 2009

University-Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelera... more University-Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. Interactions between pairs of aggregates allow their charge, mass, and gas drag to be inferred. The asymmetric charge on the aggregates causes them to rotate as they interact with each other. Through these interactions, the charge and dipole moment can be estimated and compared to numerical models.

Dust aggregates in complex plasmas have been studied theoretically in computer models, but not ex... more Dust aggregates in complex plasmas have been studied theoretically in computer models, but not extensively in an experimental setting. This work investigates several properties of aggregates which are responsible for dust dynamics: charge, dipole moment, and gas drag. A diode pumped laser is used to perturb aggregates in a GEC rf reference cell, and a high-speed camera acquires image data. Particle trajectories are extracted and analyzed to characterize or estimate values of the properties under investigation.

Plasma Sources Science and Technology, 2011

arXiv: General Physics, 2004

The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed constr... more The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed construction and calibration of a Light Gas Gun (LGG), which is used for low velocity impact studies. At geosynchronous orbit, space debris can impact commercial satellites at velocities of 500 m/s [1] reducing their useful lifetime. Additionally, there is an ever-increasing population of abandoned nonoperational satellites and related debris in these orbits [2]. Therefore, it is important to clearly understand the physics behind how such collisions can cause structural damage. This is most easily determined by measuring the damage incurred on representative material exposed to test collisions in the laboratory. Data collected in this manner will not only help illuminate the shock physics involved but can also aid in providing methods for designing advanced shielding for satellites.

Bulletin of the American Physical Society, 2019

Complex plasma containing conducting grains is common across a number of research environments. I... more Complex plasma containing conducting grains is common across a number of research environments. In space such plasmas can be formed from dust left over after the formation of stellar and protoplanetary systems where iron rich meteors, containing remnants of ...

Smith, J. York , R. Moore, M. Clyat, T. Buchs, R. Laufer, S. Attai, L. Matthews and T. W. Hyde, C... more Smith, J. York , R. Moore, M. Clyat, T. Buchs, R. Laufer, S. Attai, L. Matthews and T. W. Hyde, Center for Astrophysics, Space Physics, & Engineering Research, Baylor University, (Baylor University, Waco, Texas 76798, USA-Truell_Hyde@baylor.edu) , Educational Service Center Region 12 (2101 W Loop 340, Waco, TX 76712), Baylor School of Education (One Bear Place #97304,Waco, TX 76798-7304). La Vega Independent School District (555 TX-340 Loop, Waco, TX 76705),

A one stage Light Gas Gun (LGG) at CASPER [1] was employed to test the shielding capabilities of ... more A one stage Light Gas Gun (LGG) at CASPER [1] was employed to test the shielding capabilities of tiles composed of four different laminated nanotube combinations. These target tiles were named CSNEAT1, CSCNT1, HYCNTUT1 and HYCNTT1. For calibration purposes, a 3003- aluminum plate was also impacted and the craters formed on the various composition tiles compared.

2007 IEEE Pulsed Power Plasma Science Conference, 2007

ABSTRACT

Wakefield oscillations created by the ion wakefield existing below a dust particle within the pla... more Wakefield oscillations created by the ion wakefield existing below a dust particle within the plasma sheath generated above a powered lower electrode in a GEC rf reference cell carry information about the plasma sheath, the dust particle charge and the speed of the streaming ions. An experimental method to investigate such wakefield oscillations is discussed.

Plasma Sources Science and Technology, 2014

Using dust grains as probes in gas discharge plasma is a very promising, but at the same time ver... more 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 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.