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Mms Observations Of The Kelvin-Helmholtz Instability And Associated Ion Scale Waves, Rachel C. Rice 2022 Embry-Riddle Aeronautical University

Mms Observations Of The Kelvin-Helmholtz Instability And Associated Ion Scale Waves, Rachel C. Rice

Doctoral Dissertations and Master's Theses

The detailed mechanisms coupling the solar wind to Earth's magnetosphere are not yet fully understood. Solar wind plasma is heated non-adiabatically as it penetrates the magnetosphere, and this process must span scale sizes. Reconnection alone is not able to account for the observed heating; other mechanisms must be at work. One potential process is the Kelvin-Helmholtz instability (KHI). The KHI is a convective instability which operates at the fluid scale in plasmas, but is capable of driving secondary process at smaller scales. Previous work has shown evidence of magnetic reconnection, various ion scale wave modes, mode conversion, and turbulence associated …


Direct Current Magnetic Hall Probe Technique For Measurement Of Field Penetration In Thin Film Superconductors For Superconducting Radio Frequency Resonators, Iresha Harshani Senevirathne, Alex Gurevich, Jean Delayen 2022 Old Dominion University

Direct Current Magnetic Hall Probe Technique For Measurement Of Field Penetration In Thin Film Superconductors For Superconducting Radio Frequency Resonators, Iresha Harshani Senevirathne, Alex Gurevich, Jean Delayen

Physics Faculty Publications

Superconducting Radio Frequency (SRF) cavities used in particle accelerators are typically formed from or coated with superconducting materials. Currently, high purity niobium is the material of choice for SRF cavities that have been optimized to operate near their theoretical field limits. This brings about the need for significant R & D efforts to develop next generation superconducting materials that could outperform Nb and keep up with the demands of new accelerator facilities. To achieve high quality factors and accelerating gradients, the cavity material should be able to remain in the superconducting Meissner state under a high RF magnetic field without …


Ion Velocity Distribution Functions In Cutting-Edge Plasmas, Mitchell Cameron Paul 2022 West Virginia University

Ion Velocity Distribution Functions In Cutting-Edge Plasmas, Mitchell Cameron Paul

Graduate Theses, Dissertations, and Problem Reports

Cutting-edge plasma experiments continue to push the frontiers of plasma science. Two such groups of experiments, helicon sources and laboratory magnetic reconnection, are the focus of this thesis. The relatively high plasma density achieved for modest input powers makes helicon source plasmas ideal testbeds for fusion-relevant phenomena without the complexities associated with fusion devices. Examples include plasma-material interaction (PMI) studies, divertor region studies, and boundary physics studies. As advancements in helicon source design and technology make operation at higher power for longer times possible, understanding of the plasma dynamics, particularly ion dynamics, is vital.

Laboratory experiments are essential to advancing …


Cross-Section Measurement Of Virtual Photoproduction Of Iso-Triplet Three-Body Hypernucleus, ⋀Nn, T. Gogami, K. N. Suzuki, B. Pandey, K. Itabashi, S. Nagao, K. Okuyama, S. N. Nakamura, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J-P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T.J. Hague, O. Hansen, W. Henry, F. Hauenstein, D. W. Higinbotham, C. E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. McClellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P.E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng 2022 Old Dominion University

Cross-Section Measurement Of Virtual Photoproduction Of Iso-Triplet Three-Body Hypernucleus, ⋀Nn, T. Gogami, K. N. Suzuki, B. Pandey, K. Itabashi, S. Nagao, K. Okuyama, S. N. Nakamura, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J-P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T.J. Hague, O. Hansen, W. Henry, F. Hauenstein, D. W. Higinbotham, C. E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. Mcclellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P.E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng

Physics Faculty Publications

Missing-mass spectroscopy with the 3H(e, e′K+) reaction was carried out at Jefferson Lab’s (JLab) Hall A in Oct–Nov, 2018. The differential cross section for the 3H(γ, K+nn was deduced at ω = EeEe′ = 2.102 GeV and at the forward K+-scattering angle (0° ≤ θγK ≤ 5°) in the laboratory frame. Given typical predicted energies and decay widths, which are (BΛ, Γ) = (−0.25, 0.8) and (−0.55, 4.7) MeV, the cross sections were found …


Comparing Twins Ion Temperature Maps With Mms, Ampere, And Themis Observations During July 26, 2017 Reconnection Event, Isabella M. Householder 2022 University of New Hampshire, Durham

Comparing Twins Ion Temperature Maps With Mms, Ampere, And Themis Observations During July 26, 2017 Reconnection Event, Isabella M. Householder

Honors Theses and Capstones

The solar wind releases a constant stream of ionized particles into space which causes complex behaviors to occur within Earth’s magnetosphere. These disruptions can initiate magnetic reconnection and cause flow reversal of ions in the magnetotail. Two flow reversal events were locally detected by the Magnetospheric Multiscale Mission (MMS) on July 26, 2017 at 0700 UT and 0730 UT. The Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) provide a global measurement of heated signatures of the magnetic field and detected an increase in ion temperature during these reconnection events without the presence of a geomagnetic storm. Active Magnetosphere and Planetary Electrodynamics …


Scaling Theory Of 3d Magnetic Reconnection X-Line Spreading, Milton Arencibia 2022 West Virginia University

Scaling Theory Of 3d Magnetic Reconnection X-Line Spreading, Milton Arencibia

Graduate Theses, Dissertations, and Problem Reports

Magnetic reconnection is fundamental process in plasmas that converts magnetic energy into kinetic and thermal energy via a change in magnetic topology. Magnetic reconnection is known to mediate eruptive solar flares, geomagnetic substorms that create the Northern lights, heating and particle acceleration in controlled fusion devices, and is thought to be an important process in numerous settings in high-energy astrophysics. Classical models of reconnection are two-dimensional (2D), but naturally occurring reconnection is three-dimensional (3D), and a manifestation of the 3D nature is that the x-line where the magnetic field topology changes has a finite extent in the direction normal to …


Numerical Investigations Of 2-D Magnetic Nozzles On Pulsed Plasma Plumes, Joshua Daniel Burch 2022 Missouri University of Science and Technology

Numerical Investigations Of 2-D Magnetic Nozzles On Pulsed Plasma Plumes, Joshua Daniel Burch

Masters Theses

"This research presents studies of a novel type of magnetic nozzle that allows for three-dimensional (3-D) steering of a plasma plume. Numerical simulations were performed using Tech-X's USim® software to quantify the nozzle's capabilities. A2-D planar magnetic nozzle was applied to plumes of a nominal pulsed inductive plasma (PIP) source with discharge parameters similar to those of Missouri S&T's Missouri Plasmoid Experiment (MPX). Argon and xenon plumes were considered. Simulations were verified and validated through a mesh convergence study as well as comparison with available experimental data. Periodicity was achieved over the simulation run time and phase angle samples were …


Beamline For E-Beam Processing At Uitf, G. Ciovati, C. Bott, S. Gregory, F. Hannon, Xi Li, M. McCaughan, R. Pearce, M. Poelker, H. Vennekate 2022 Old Dominion University

Beamline For E-Beam Processing At Uitf, G. Ciovati, C. Bott, S. Gregory, F. Hannon, Xi Li, M. Mccaughan, R. Pearce, M. Poelker, H. Vennekate

Electrical & Computer Engineering Faculty Publications

No abstract provided.


Grand Challenges In Low Temperature Plasmas, XinPei Lu, Peter J. Bruggeman, Stephan Reuter, George Naidis, Annemie Bogaerts, Mounir Laroussi, Michael Keidar, Eric Robert, Jean-Michel Pouvesle, DaWei Liu, Kostya (Ken) Ostrikov 2022 Old Dominion University

Grand Challenges In Low Temperature Plasmas, Xinpei Lu, Peter J. Bruggeman, Stephan Reuter, George Naidis, Annemie Bogaerts, Mounir Laroussi, Michael Keidar, Eric Robert, Jean-Michel Pouvesle, Dawei Liu, Kostya (Ken) Ostrikov

Electrical & Computer Engineering Faculty Publications

Low temperature plasmas (LTPs) enable to create a highly reactive environment at near ambient temperatures due to the energetic electrons with typical kinetic energies in the range of 1 to 10 eV (1 eV = 11600K), which are being used in applications ranging from plasma etching of electronic chips and additive manufacturing to plasma-assisted combustion. LTPs are at the core of many advanced technologies. Without LTPs, many of the conveniences of modern society would simply not exist. New applications of LTPs are continuously being proposed. Researchers are facing many grand challenges before these new applications can be translated to practice. …


Microwave Enhanced Electron Energy Distribution Functions, John Samuel McKee 2022 West Virginia University

Microwave Enhanced Electron Energy Distribution Functions, John Samuel Mckee

Graduate Theses, Dissertations, and Problem Reports

The use of two (or more) radio frequency (RF) sources at different frequencies is a common technique in the plasma processing industry to control ion energy characteristics separately from plasma generation. A similar approach is presented here with the focus on modifying the electron population in argon and helium plasmas. The plasma is generated by a helicon source at a frequency f0 = 13.56 MHz. Microwaves of frequency f1 = 2.45 GHz are then injected into the helicon source chamber perpendicular to the background magnetic field. The microwaves damp on the electrons via R-mode (anti-parallel to the background magnetic field …


Edge Fueling And Neutral Density Studies Of The Alcator C-Mod Tokamak Using The Solps-Iter Code, Richard M. Reksoatmodjo 2022 William & Mary - Arts & Sciences

Edge Fueling And Neutral Density Studies Of The Alcator C-Mod Tokamak Using The Solps-Iter Code, Richard M. Reksoatmodjo

Dissertations, Theses, and Masters Projects

Understanding edge neutral dynamics in high-field tokamaks has strong consequencesfor both fueling and plasma profile predictions. We validate the ability of SOLPS-ITER, a 2D fluid plasma/kinetic Monte Carlo neutral code, to accurately model the upstream neutral density profiles of L-mode, I-mode, and H-mode discharges in the Alcator CMod tokamak, for which Lyman-alpha emission measurements were available. We achieve simulated Lyman-alpha emission and neutral density profiles that are within one standard deviation of empirically inferred profiles for all three discharges, via iterative tuning of the perpendicular transport coefficient profiles alone, providing confidence in the conclusion that while further physics (drifts, impurities, …


A Laser Frequency Transverse Modulation Might Compensate For The Spectral Broadening Due To Large Electron Energy Spread In Thomson Sources, Vittoria Petrillo, Illya Drebot, Geoffrey Krafft, Cesare Maroli, Andrea R. Rossi, Marcello Rossetti Conti, Marcel Ruijter, Balša Terzić 2022 Old Dominion University

A Laser Frequency Transverse Modulation Might Compensate For The Spectral Broadening Due To Large Electron Energy Spread In Thomson Sources, Vittoria Petrillo, Illya Drebot, Geoffrey Krafft, Cesare Maroli, Andrea R. Rossi, Marcello Rossetti Conti, Marcel Ruijter, Balša Terzić

Physics Faculty Publications

Compact laser plasma accelerators generate high-energy electron beams with increasing quality. When used in inverse Compton backscattering, however, the relatively large electron energy spread jeopardizes potential applications requiring small bandwidths. We present here a novel interaction scheme that allows us to compensate for the negative effects of the electron energy spread on the spectrum, by introducing a transverse spatial frequency modulation in the laser pulse. Such a laser chirp, together with a properly dispersed electron beam, can substantially reduce the broadening of the Compton bandwidth due to the electron energy spread. We show theoretical analysis and numerical simulations for hard …


Impurity Production And Transport In The Prototype Material Plasma Exposure Experiment, Clyde J. Beers 2021 University of Tennessee, Knoxville

Impurity Production And Transport In The Prototype Material Plasma Exposure Experiment, Clyde J. Beers

Doctoral Dissertations

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear pulse plasma device at Oak Ridge National Laboratory with the purpose of doing the research and development for the heating concepts on the planned full MPEX device. The goal of MPEX is to perform material studies at fusion relevant conditions. To understand the conditions at the material target for performing plasma-material interaction studies the ion temperature and density, the electron temperature and density, and the particle flux and fluence must be known. Impurities within Proto-MPEX can alter the desired conditions at the material target and need to be understood for …


Plasma-Laser Wakefield Acceleration, Jonathan Babu 2021 California Polytechnic State University, San Luis Obispo

Plasma-Laser Wakefield Acceleration, Jonathan Babu

Physics

Many texts detailing the derivations and science of Wakefield Acceleration are aimed at graduate and doctorate level scholars, and these may seem intimidating to new physics students. This paper is meant to be an introduction to the nature of plasmas, lasers, laser-plasma interactions, and Laser Wakefield Acceleration (LWFA), with sources given where extra detail may be required. I recognize that this paper is not meant to be an all-encompassing review on the nature of the topics, as these topics are complex and subject of entire textbooks. Instead, I aim to provide an introduction to these topics to a college-level scholar …


Spatiotemporal Non-Uniformly Correlated Beams, Milo W. Hyde IV 2021 Air Force Institute of Technology

Spatiotemporal Non-Uniformly Correlated Beams, Milo W. Hyde Iv

Faculty Publications

We present a new partially coherent source with spatiotemporal coupling. The stochastic light, which we call a spatiotemporal (ST) non-uniformly correlated (NUC) beam, combines space and time in an inhomogeneous (shift- or space-variant) correlation function. This results in a source that self-focuses at a controllable location in space-time, making these beams potentially useful in applications such as optical trapping, optical tweezing, and particle manipulation. We begin by developing the mutual coherence function for an ST NUC beam. We then examine its free-space propagation characteristics by deriving an expression for the mean intensity at any plane z ≥ 0. To validate …


Ultra-Low Frequency Waves At Middle Latitudes During Substorms: Observations And Modeling, Mergen Alimaganbetov 2021 Embry-Riddle Aeronautical University

Ultra-Low Frequency Waves At Middle Latitudes During Substorms: Observations And Modeling, Mergen Alimaganbetov

Doctoral Dissertations and Master's Theses

This doctoral dissertation presents the results of investigation of the Ultra-Low Frequency (ULF) waves at middle latitudes during substorms. The dissertation consists of two major parts, observations and simulations. The research in this dissertation proposes that the main role in the generation of ULF waves at middle latitudes during substorm belongs to the plasmapause.

The first part of the dissertation presents results of the data analysis of 84 intense substorm events as well as an overview of space observation programs such as CRRES, Van Allen Probes and DMSP. Data used in this study are from the ACE satellite taken measurements …


Improvements To Emissive Plume And Shock Wave Diagnostics And Interpretation During Pulsed Laser Ablation Of Graphite, Timothy I. Calver 2021 Air Force Institute of Technology

Improvements To Emissive Plume And Shock Wave Diagnostics And Interpretation During Pulsed Laser Ablation Of Graphite, Timothy I. Calver

Theses and Dissertations

This dissertation covers nanosecond pulsed laser ablation of graphite for 4-5.7 J/cm2 fluences with 248 nm and 532 nm lasers in 1-180 Torr helium, argon, nitrogen, air, and mixed gas. Three experiments were performed to improve the interpretation of common diagnostics used to characterize pulsed laser ablation, find simple but universal scaling relationships for comparing dynamics across different materials and ablation conditions, and provide a systematic analysis of graphite emissive plume and shock wave dynamics. A scaling of the Sedov-Taylor energy ratio was developed and validated for a range of studies despite differences in wavelength, pulse duration, fluence, and …


The Impact Of Laser Control On The Porosity And Microstructure Of Selective Laser Melted Nickel Superalloy 718, Travis E. Shelton, Gregory R. Cobb, Carl R. Hartsfield, Benjamin M. Doane, Cayla C. Eckley, Ryan A. Kemnitz 2021 Air Force Institute of Technology

The Impact Of Laser Control On The Porosity And Microstructure Of Selective Laser Melted Nickel Superalloy 718, Travis E. Shelton, Gregory R. Cobb, Carl R. Hartsfield, Benjamin M. Doane, Cayla C. Eckley, Ryan A. Kemnitz

Faculty Publications

Additively manufacturing high performance metals by laser processing represents an exciting opportunity to exploit localized properties by varying input parameters throughout the process. This work explores the solidification and microstructural properties of selectively laser melted (SLM) Inconel 718 (IN718) using unique processing parameters. By employing traditional pulsed laser physics techniques, samples were manufactured with a continuous wave laser to study a potential ubiquitous approach. While the overall power density was controlled, the power, speed, and hatch spacing were varied. The porosity and grain sizes of the samples were characterized by optical and scanning electron microscopes. The influence of processing parameters …


Multi-Gaussian Random Variables For Modeling Optical Phenomena, Olga Korotkova, Milo W. Hyde IV 2021 University of Miami

Multi-Gaussian Random Variables For Modeling Optical Phenomena, Olga Korotkova, Milo W. Hyde Iv

Faculty Publications

A generalization of the classic Gaussian random variable to the family of multi-Gaussian (MG) random variables characterized by shape parameter M > 0, in addition to the mean and the standard deviation, is introduced. The probability density function (PDF) of the MG family members is an alternating series of Gaussian functions with suitably chosen heights and widths. In particular, for integer values of M, the series has a finite number of terms and leads to flattened profiles, while reducing to the classic Gaussian PDF for M = 1. For non-integer, positive values of M, a convergent infinite series of …


A Study Of Systematic Uncertainties For A Photon-Like Low Energy Excess Search At Microboone, Gray Yarbrough 2021 University of Tennessee, Knoxville

A Study Of Systematic Uncertainties For A Photon-Like Low Energy Excess Search At Microboone, Gray Yarbrough

Doctoral Dissertations

The premise of this dissertation is the study of and reduction of systematic uncertainties in the MicroBooNE experiment at the Fermi National Accelerator Laboratory. MicroBooNE is a short-baseline oscillation experiment using the innovative liquid argon time projection chamber technology to study, with unprecedented detail, neutrino interactions. The primary goal of MicroBooNE is the investigation of the MiniBooNE low energy excess (LEE) of electron neutrino events, a result which raised fundamental questions on the existence of sterile neutrinos with broad implications to the field of particle physics. The principal study of this dissertation is a study of systematics as part of …


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