9 - Gas Kinetic Model For Argon In A Commercial Plasma System, 2018 Valdosta State University
9 - Gas Kinetic Model For Argon In A Commercial Plasma System, Zachary Barton
Georgia Undergraduate Research Conference (GURC)
Gas kinetic models can tell us a lot about how a plasma system operates on the atomic and/or molecular level. Here, we are using a commercial Boltzmann solver to determine the electron energy distribution functions associated with an argon plasma produced by a commercial plasma system. From the EEDF we can gain insight about the electron temperature and electric field inside the device.
Transition Radiation As A Probe Of The Chiral Anomaly, 2018 Fudan University
Transition Radiation As A Probe Of The Chiral Anomaly, Xu-Guang Huang, Kirill Tuchin
Physics and Astronomy Publications
A fast charged particle crossing the boundary between chiral matter and vacuum radiates transition radiation. Its most remarkable features—the resonant behavior at a certain emission angle and the circular polarization of the spectrum—depend on the parameters of the chiral anomaly in a particular material or matter. Chiral transition radiation can be used to investigate the chiral anomaly in such diverse media as the quark-gluon plasma, Weyl semimetals, and axionic dark matter.
Effects Of Fabrication Errors On The Focusing Performance Of A Sector Metalens, 2018 Samara National Research University and RAS – Branch of the FSRC “Crystallography and Photonics” RAS, Molodogvardeyskaya 151, 443001, Samara, Russia
Effects Of Fabrication Errors On The Focusing Performance Of A Sector Metalens, S. S. Stafeev, A. G. Nalimov, Liam O’Faolain, M. V. Kotlyar
Using e-beam lithography, a 16-sector spiral metalens was fabricated in an amorphous silicon, capable of converting linearly polarized incident light into an azimuthally polarized optical vortex. When illuminated by a 633-nm linearly polarized laser beam, the metalens generated a near-surface subwavelength focal spot equal to 0.75 of the incident wavelength at full-width of half-maximum intensity. The focusing performance of the spiral metalens was numerically shown to be sensitive to the deviation of the factual microrelief from the calculated height. For the designed microrelief height, a circularly polarized incident beam was focused into a bright ring with a reverse energy ...
Investigation On The Rons And Bactericidal Effects Induced By He + O2 Cold Plasma Jets: In Open Air And In An Airtight Chamber, Han Xu, Dingxin Liu, Weitao Wang, Zhijie Liu, Li Guo, Mingzhe Rong, Michael G. Kong
He + O2 plasma jets in open air and in an airtight chamber are comparatively studied, with respect to their production of gaseous/aqueous reactive species and their antibacterial effects. Under the same discharge power, the plasma jet in open air has higher densities of gaseous reactive species and a higher concentration of aqueous H2O2 but lower concentrations of aqueous OH and O2-. In addition, the increase in the O2 ratio in He in both plasma jets causes a linear decrease in the population of gaseous reactive species, except for O(3p5P) when ...
Perturbative Representation Of Ultrashort Nonparaxial Elegant Laguerre-Gaussian Fields, 2018 University of Nebraska - Lincoln
Perturbative Representation Of Ultrashort Nonparaxial Elegant Laguerre-Gaussian Fields, Andrew Vikartofsky, Anthony F. Starace, Liang-Wen Pi
Anthony F. Starace Publications
An analytical method for calculating the electromagnetic fields of a nonparaxial elegant Laguerre-Gaussian (LG) vortex beam is presented for arbitrary pulse duration, spot size, and LG mode. This perturbative approach provides a numerically tractable model for the calculation of arbitrarily high radial and azimuthal LG modes in the nonparaxial regime, without requiring integral representations of the fields. A key feature of this perturbative model is its use of a Poisson-like frequency spectrum, which allows for the proper description of pulses of arbitrarily short duration. This model is thus appropriate for simulating laser-matter interactions, including those involving short laser pulses.
Significance Of A Non-Thermal Plasma Treatment On Ldpe Biodegradation With Pseudomonas Aeruginosa, 2018 Technological University Dulbin
Significance Of A Non-Thermal Plasma Treatment On Ldpe Biodegradation With Pseudomonas Aeruginosa, Laurence Scally, Miroslav Gulan, Lars Weigang, Patrick Cullen, Vladimir Milosavljevic
The use of plastics has spanned across almost all aspects of day to day life. Although their uses are invaluable, they contribute to the generation of a lot of waste products that end up in the environment and end up polluting natural habitats such as forests and the ocean. By treating low-density polyethylene (LDPE) samples with non-thermal plasma in ambient air and with an addition of 4% CO2, the biodegradation of the samples can be increased due to an increase in oxidative species causing better cell adhesion and acceptance on the polymer sample surface. It was, however, found that the ...
Gas Pressure Dependence Of Microwave Pulses Generated By Laser-Produced Filament Plasmas, 2018 Air Force Research Laboratory
Gas Pressure Dependence Of Microwave Pulses Generated By Laser-Produced Filament Plasmas, Alexander Englesbe, Jennifer Elle, Remington Reid, Adrian Lucero, Hugh Pohle, Matthew Domonkos, Serge Y. Kalmykov, Karl Krushelnick, Andreas Schmitt-Sody
Serge Youri Kalmykov
Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, 2018 Air Force Institute of Technology
Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman
Theses and Dissertations
A solver for Poisson's equation was developed using the Radix-2 FFT method first invented by Carl Friedrich Gauss. Its performance was characterized using simulated data and identical boundary conditions to those found in a Hall Effect Thruster. The characterization showed errors below machine-zero with noise-free data, and above 20% noise-to-signal strength, the error increased linearly with the noise. This solver can be implemented into AFRL's plasma simulator, the Thermophysics Universal Research Framework (TURF) and used to quickly and accurately compute the electric field based on charge distributions. The validity of a machine learning approach and data-based complex system ...
Finite-Size Effects In Metasurface Lasers Based On Resonant Dark States, 2018 Institute of Electronic Structure & Laser, FORTH
Finite-Size Effects In Metasurface Lasers Based On Resonant Dark States, Sotiris Droulias, Thomas Koschny, Costas M. Soukoulis
Ames Laboratory Accepted Manuscripts
The quest for subwavelength coherent light sources has recently led to the exploration of dark-mode based surface lasers, which allow for independent adjustment of the lasing state and its coherent radiation output. To understand how this unique design performs in real experiments, we need to consider systems of finite size and quantify finite-size effects not present in the infinite dark-mode surface laser model. Here we find that, depending on the size of the system, distinct and even counterintuitive behavior of the lasing state is possible, determined by a balanced competition between multiple loss channels, including dissipation, intentional out-coupling of coherent ...
A Review Of Equation-Of-State Models For Inertial Confinement Fusion Materials, 2018 Lawrence Livermore National Laboratory
A Review Of Equation-Of-State Models For Inertial Confinement Fusion Materials, J. A. Gaffney, Duane D. Johnson, Andrey Smirnov, Et Al.
Ames Laboratory Accepted Manuscripts
Material equation-of-state (EOS) models, generally providing the pressure and internal energy for a given density and temperature, are required to close the equations of hydrodynamics. As a result they are an essential piece of physics used to simulate inertial confinement fusion (ICF) implosions. Historically, EOS models based on different physical/chemical pictures of matter have been developed for ICF relevant materials such as the deuterium (D2) or deuterium-tritium (DT) fuel, as well as candidate ablator materials such as polystyrene (CH), glow-discharge polymer (GDP), beryllium (Be), carbon (C), and boron carbide (B4C). The accuracy of these EOS models can directly affect ...
Incorporating Collisions And Resistance Into The Transition From Field Emission To The Space Charge Regime, Samuel D. Dynako, Adam M. Darr, Allen L. Garner
The Summer Undergraduate Research Fellowship (SURF) Symposium
Advancements in microelectromechanical systems (MEMS) and microplasmas, particularly with respect to applications in combustion and biotechnology, motivate studies into microscale gas breakdown to enable safe system design and implementation. Breakdown at microscale deviates from that predicted by Paschen’s law due to field emission—the stripping of electrons from the cathode in the presence of strong surface field—and follows the Fowler-Nordheim (FN) law. As injected current increases at this length scale, electrons accumulate in the gap and FN electron emission becomes space charge limited, leading to the Child-Langmuir (CL) law at vacuum and the Mott-Gurney (MG) law at high ...
High-Brilliance, High-Flux Compact Inverse Compton Light Source, 2018 Old Dominion University
High-Brilliance, High-Flux Compact Inverse Compton Light Source, K. E. Deitrick, G. A. Krafft, B. Terzić, J. R. Delayen
Physics Faculty Publications
The Old Dominion University Compact Light Source (ODU CLS) design concept is presented-a compact Inverse Compton Light Source (ICLS) with flux and brilliance orders of magnitude beyond conventional laboratory-scale sources and greater than other compact ICLS designs. This concept utilizes the physics of inverse Compton scattering of an extremely low emittance electron beam by a laser pulse of rms length of approximately two-thirds of a picosecond (2/3 ps). The accelerator is composed of a superconducting radio frequency (SRF) reentrant gun followed by four double-spoke SRF cavities. After the linac are three quadrupole magnets to focus the electron beam to ...
Compton Scattering From The Deuteron Above Pion-Production Threshold, 2018 Nikhef, The Netherlands
Compton Scattering From The Deuteron Above Pion-Production Threshold, B. Strandberg, J. R. M. Annand, W. Briscoe, J. Brudvik, F. Cividini, L. Clark, E. J. Downie, K. England, G. Feldman, K. G. Fissum, D. I. Glazier, K. Hamilton, K. Hansen, L. Isaksson, R. Al Jebali, Michael A. Kovash, S. Lipschutz, M. Lundin, M. Meshkian, D. G. Middleton, L. S. Myers, D. O'Donnell, G. O'Rielly, B. Oussena, M. F. Preston, B. Schröder, B. Seitz, I. Strakovsky, M. Taragin
Physics and Astronomy Faculty Publications
The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data on light nuclear targets. Recent measurements of the differential cross section for Compton scattering on the deuteron below the pion-production threshold have decreased the uncertainties in the neutron polarizabilities, yet the proton polarizabilities remain known substantially more accurately. As the sensitivity of the cross section to the polarizabilities increases with incident photon energy, measurements above the pion threshold may offer a way for an improved determination of the neutron polarizabilities. In this Rapid ...
Laser-Induced Recoverable Surface Patterning On Ni50ti50 Shape Memory Alloys, 2018 Western Kentucky University
Laser-Induced Recoverable Surface Patterning On Ni50ti50 Shape Memory Alloys, Saidjafarzoda Ilhom
Masters Theses & Specialist Projects
Shape memory alloys (SMAs) are a unique class of smart materials exhibiting extraordinary properties with a wide range of applications in engineering, biomedical, and aerospace technologies. In this study, an advanced, efficient, low-cost, and highly scalable laser-assisted imprinting method with low environmental impact to create thermally controllable surface patterns is reported. Two different imprinting methods were carried out mainly on Ni50Ti50 (at. %) SMAs by using a nanosecond pulsed Nd:YAG laser operating at 1064 nm wavelength and 10 Hz frequency. First, laser pulses at selected fluences were directly focused on the NiTi surface, which generated pressure pulses of up to ...
Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, 2018 Old Dominion University
Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, Seyed Hamid Razavi Barzoki
Electrical & Computer Engineering Theses & Disssertations
A non-thermal transient diffuse plasma can be generated remotely in a nonconductive reduced pressure chamber by an external guided fast ionization wave (FIW). We found that an atmospheric-pressure low-temperature plasma jet (APPJ) can be a source of FIW which transfers an enhanced electric field at the wave front across a reduced pressure Pyrex glass chamber with no electrical connection to the chamber. Here, we studied the formation and propagation of the APPJ plasma, the interaction of atmospheric-pressure guided FIW with a dielectric surface which forms the wall of the reduced-pressure system, and the formation and propagation of the reduce-pressure FIW ...
Control Of Harmonic Generation By The Time Delay Between Two-Color, Bicircular Few-Cycle Mid-Ir Laser Pulses, 2018 Voronezh State University, Russia
Control Of Harmonic Generation By The Time Delay Between Two-Color, Bicircular Few-Cycle Mid-Ir Laser Pulses, M. V. Frolov, N. L. Manakov, A. A. Minina, N. V. Vvedenskii, A. A. Silaev, M. Yu. Ivanov, Anthony F. Starace
Anthony F. Starace Publications
We study control of high-order harmonic generation (HHG) driven by time-delayed, few-cycle ω and 2ω counterrotating mid-IR pulses. Our numerical and analytical study shows that the time delay between the two-color pulses allows control of the harmonic positions, both those allowed by angular momentum conservation and those seemingly forbidden by it. Moreover, the helicity of any particular harmonic is tunable from left to right circular without changing the driving pulse helicity. The highest HHG yield occurs for a time delay comparable to the fundamental period T = 2π/ω.
Production Of Photoionized Plasmas In The Laboratory With X-Ray Line Radiation, 2018 Queen's University Belfast, UK
Production Of Photoionized Plasmas In The Laboratory With X-Ray Line Radiation, S. White, R. Irwin, J. R. Warwick, G. F. Gribakin, G. Sarri, F. P. Keenan, D. Riley, S. J. Rose, E. G. Hill, Gary J. Ferland, B. Han, F. Wang, G. Zhao
Physics and Astronomy Faculty Publications
In this paper we report the experimental implementation of a theoretically proposed technique for creating a photoionized plasma in the laboratory using x-ray line radiation. Using a Sn laser plasma to irradiate an Ar gas target, the photoionization parameter, ξ = 4πF/Ne, reached values of order 50erg cm s−1, where F is the radiation flux in erg cm−2 s−1. The significance of this is that this technique allows us to mimic effective spectral radiation temperatures in excess of 1 keV. We show that our plasma starts to be collisionally dominated before the peak of the ...
Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By Association And Carbon-Carbon Bond Cleavage Of Isoprene, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang
Chemistry Faculty Publications
La atom reaction with isoprene is carried out in a laser-vaporization molecular beam source. The reaction yields an adduct as the major product and C—C cleaved and dehydrogenated species as the minor ones. La(C5H8), La(C2H2), and La(C3H4) are characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectra of all three species exhibit a strong origin band and several weak vibronic bands corresponding to La-ligand stretch and ligand-based bend excitations. La(C5H8) is a five-membered metallacycle, whereas La(C2 ...
Diffraction Of Laguerre Gaussian Vortex Beams, 2018 University of Arkansas, Fayetteville
Diffraction Of Laguerre Gaussian Vortex Beams, Anindya Ambuj
Theses and Dissertations
The natural phenomenon of waves bending around obstacles is diffraction. Spatial characteristics of the diffraction pattern depends on the incident wave field, the shape, and size of the aperture. The diffraction of a plane wave of light by a slit and a circular aperture produce the sinc-squared and the Airy intensity patterns, respectively. On the contrary, the diffraction of Laguerre-Gauss vortex (LGV) beams by simple apertures such as a slit, circular apertures, and polygons show many unexpected features.
LGV beams have ρ ` e i`φ transverse spatial dependence, where ρ is the distance from the beam axis, φ the azimuthal ...
Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, 2018 University of Nebraska - Lincoln
Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, Dian Peng, M. V. Frolov, Liang-Wen Pi, Anthony F. Starace
Anthony F. Starace Publications
We present a theoretical analysis showing how chirp can be used to sculpt two-color driving laser field waveforms in order to enhance high-order harmonic generation (HHG) and/or extend HHG cutoff energies. Specifically, we consider driving laser field waveforms composed of two ultrashort pulses having different carrier frequencies in each of which a linear chirp is introduced. Two pairs of carrier frequencies of the component pulses are considered: (ω, 2ω) and (ω, 3ω). Our results show how changing the signs of the chirps in each of the two component pulses leads to drastic changes in the HHG spectra. Our theoretical ...