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Articles 1 - 16 of 16
Full-Text Articles in Plasma and Beam Physics
Tokamak 3d Heat Load Investigations Using An Integrated Simulation Framework, Thomas Looby
Tokamak 3d Heat Load Investigations Using An Integrated Simulation Framework, Thomas Looby
Doctoral Dissertations
Reactor class nuclear fusion tokamaks will be inherently complex. Thousands of interconnected systems that span orders of magnitude in physical scale must operate cohesively for the machine to function. Because these reactor class tokamaks are all in an early design stage, it is difficult to quantify exactly how each subsystem will act within the context of the greater systems. Therefore, to predict the engineering parameters necessary to design the machine, simulation frameworks that can model individual systems as well as the interfaced systems are necessary. This dissertation outlines a novel framework developed to couple otherwise disparate computational domains together into …
Mms Observations Of The Kelvin-Helmholtz Instability And Associated Ion Scale Waves, Rachel C. Rice
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 …
Ultra-Low Frequency Waves At Middle Latitudes During Substorms: Observations And Modeling, Mergen Alimaganbetov
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 …
Stellarator Optimization With Poloidal Field Coils, Haley Wilson, Andrew Ware, Aaron Bader, Chris Hegna
Stellarator Optimization With Poloidal Field Coils, Haley Wilson, Andrew Ware, Aaron Bader, Chris Hegna
Undergraduate Theses, Professional Papers, and Capstone Artifacts
Stellarators are devices that use magnetic fields to optimize the conditions needed for plasmas to undergo fusion. Unlike tokamaks, stellarators do not rely on a plasma current but can produce a helical magnetic field using only external coils. In a stellarator, the coils surrounding the plasma are called modular coils and those that follow the plasma are called poloidal field coils. Modular coils can be difficult to build if they are too complex. An effort is underway to develop coil conditions that meet both physics and engineering constraints. The FOCUS code was developed to flexibly optimize stellarator coil configurations [C. …
Investigation Of Mnxni1-Xo Thin Films Using Pulsed Laser Deposition, Md Ashif Anwar
Investigation Of Mnxni1-Xo Thin Films Using Pulsed Laser Deposition, Md Ashif Anwar
MSU Graduate Theses
The exchange bias (EB) effect, especially in nanomaterials, is highly promising for use in antiferromagnet-based spintronics applications. NiO is a well known antiferromagnetic material with a high Néel temperature (525K) and can exhibit ferromagnetism/ ferrimagnetism by adding other magnetic transition elements. Our previous work has shown that the antiferromagnetic characteristics of conventional NiO insulating nanostructured material can be altered to have substantial ferrimagnetic characteristics by doping NiO with Mn or Co. Pulsed laser deposition (PLD) was used to grow heterostructures comprised of a nanostructured thin NiO film deposited on the surface of a MgO (100) and Al2O3 …
Optimizing Llrf Parameters In The Electron-Ion Collider, William M. Bjorndahl
Optimizing Llrf Parameters In The Electron-Ion Collider, William M. Bjorndahl
Physics
To improve particle interaction in the future Electron-Ion Collider (EIC), we investigated different feedback implementations to control the accelerating voltage and examined the power and beam phase for each instance. Using MATLAB, we studied three feedback mechanisms: Direct, One Turn, and Feedforward. Enacting feedforward yielded the best performance. To minimize the klystron power consumption, we analyzed different Low-Level Radio Frequency (LLRF) parameters such as detuning. Combining theory and simulated results, we found the optimal detuning value that minimizes klystron power consumption.
Optical Response Analysis Of Thz Photoconductive Antenna Using Comsol Multiphysics, Jose Isaac Santos Batista
Optical Response Analysis Of Thz Photoconductive Antenna Using Comsol Multiphysics, Jose Isaac Santos Batista
Electrical Engineering Undergraduate Honors Theses
A THz photoconductive antenna consists of antenna pads laid over a photoconductive substrate. These types of antennas are excited through the application of an optical pump (laser), which generates carriers inside the semiconductor. The acceleration and recombination of these carriers produce photocurrent that excites the antenna and generates THz pulse. This thesis focuses on analyzing the optical response of a photoconductive antenna, which consist of the interaction of the incident electric field of a laser pump with the radiating device. It develops the amplitude modulation process of a plane wave of light into a laser pump. It also takes into …
Magnetic Anisotropy And Exchange Bias In L10 Fept/Nio Bilayer Thin Films, Zachary B. Leuty
Magnetic Anisotropy And Exchange Bias In L10 Fept/Nio Bilayer Thin Films, Zachary B. Leuty
MSU Graduate Theses
Perpendicular exchange bias (PEB), particularly when it persists in nanomaterials to room temperature, is highly useful for applications in spintronic devices and for advancing the development of high-information-density magnetic random access memory. A complete mechanistic and theoretical understanding of exchange bias has evaded scientists. The quest to discover novel materials for magnetic and spintronic device applications has stimulated investigation into nanomaterials having optimal and/or tailored magnetic properties that are based on the exchange bias effect. In this study, pulsed laser deposition was used to grow epitaxial PEB systems of ferromagnetic FePt thin film layers that are interfaced with antiferromagnetic NiO …
Instrument Design Optimization With Computational Methods, Michael H. Moore
Instrument Design Optimization With Computational Methods, Michael H. Moore
Physics Theses & Dissertations
Using Finite Element Analysis to approximate the solution of differential equations, two different instruments in experimental Hall C at the Thomas Jefferson National Accelerator Facility are analyzed. The time dependence of density fluctuations from the liquid hydrogen (LH2) target used in the Qweak experiment (2011-2012) are studied with Computational Fluid Dynamics (CFD) and the simulation results compared to data from the experiment. The 2.5 kW liquid hydrogen target was the highest power LH2 target in the world and the first to be designed with CFD at Jefferson Lab. The first complete magnetic field simulation of the Super High Momentum …
Spontaneous Parametric Down Conversion Of Photons Through Β-Barium Borate, Luke Horowitz
Spontaneous Parametric Down Conversion Of Photons Through Β-Barium Borate, Luke Horowitz
Physics
An apparatus for detecting pairs of entangled 405nm photons that have undergone Spontaneous Parametric Down Conversion through β-Barium Borate is described. By using avalanche photo-diodes to detect the low-intensity converted beam and a coincidence module to register coincident photons, it is possible to create an apparatus than can be used to perform quantum information experiments under a budget appropriate for an undergraduate physics lab.
Improving The Efficiency And Resolution Of Time Of Flight (Tof) Mass Spectrometer For Magnetospheric Applications., Zain Abbas
Honors Theses and Capstones
The Earth magnetosphere is the volume of space formed by the Earth magnetic field in response to the flow of plasma from the solar wind. Although the magnetopause shields us from the solar wind there are far more particles that penetrate with energy, and momentum to the Earths magnetosphere and interacts with the Earth’s magnetic field to create various plasmas and currents which shape and couple different regions of magnetosphere. The study of the dynamics of ions in and outside of the magnetosphere is done through mass spectrometer. Over the years, CODIF Ion TOF spectrometer have been used to understand …
Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei
Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei
Electronic Thesis and Dissertation Repository
One of the main goals of applied electrostatics engineering is to discover new perspectives in a wide range of research areas. Controlling the fluid media through electrostatic forces has brought new important scientific and industrial applications. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in the field of fluid dynamics. Although numerous EHD applications have been explored and extensively studied so far, most of the works are either experimental studies, which are not capable to explain the in depth physics of the phenomena, or detailed analytical studies, which are not time effective. The focus of this study is …
Langmuir Probe Instrument Suite For Mesosphere Turbulence Experiment Mission, Adam Blake
Langmuir Probe Instrument Suite For Mesosphere Turbulence Experiment Mission, Adam Blake
Doctoral Dissertations and Master's Theses
The Langmuir probe technique is the predominant in-situ plasma diagnostic technique, and is arguably the only measurement technique that is universally own on every sounding rocket investigation. Earth's mesosphere region (80-120 km) is a host of many dynamic phenomena such as the noctilucent clouds, breaking gravity waves, inversion layers, settlement of mesospheric smoke particles, etc. As such it is critical to have a comprehensive suite of plasma diagnostics that can unambiguously measure various plasma parameters.
This thesis deals with the development and testing of three different Langmuir probe implementations suitable for investigation of the mesosphere which are to be launched …
Fully Coupled Fluid And Electrodynamic Modeling Of Plasmas: A Two-Fluid Isomorphism And A Strong Conservative Flux-Coupled Finite Volume Framework, Richard Joel Thompson
Fully Coupled Fluid And Electrodynamic Modeling Of Plasmas: A Two-Fluid Isomorphism And A Strong Conservative Flux-Coupled Finite Volume Framework, Richard Joel Thompson
Doctoral Dissertations
Ideal and resistive magnetohydrodynamics (MHD) have long served as the incumbent framework for modeling plasmas of engineering interest. However, new applications, such as hypersonic flight and propulsion, plasma propulsion, plasma instability in engineering devices, charge separation effects and electromagnetic wave interaction effects may demand a higher-fidelity physical model. For these cases, the two-fluid plasma model or its limiting case of a single bulk fluid, which results in a single-fluid coupled system of the Navier-Stokes and Maxwell equations, is necessary and permits a deeper physical study than the MHD framework. At present, major challenges are imposed on solving these physical models …
Study Of A Non-Equilibrium Plasma Pinch With Application For Microwave Generation, Ahmad Al Agry
Study Of A Non-Equilibrium Plasma Pinch With Application For Microwave Generation, Ahmad Al Agry
UNLV Theses, Dissertations, Professional Papers, and Capstones
The Non-Equilibrium Plasma Pinch (NEPP), also known as the Dense Plasma Focus (DPF) is well known as a source of energetic ions, relativistic electrons and neutrons as well as electromagnetic radiation extending from the infrared to X-ray. In this dissertation, the operation of a 15 kJ, Mather type, NEPP machine is studied in detail. A large number of experiments are carried out to tune the machine parameters for best performance using helium and hydrogen as filling gases. The NEPP machine is modified to be able to extract the copious number of electrons generated at the pinch. A hollow anode with …
The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman
The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The purpose of this thesis is to investigate whether it is feasible to use Langmuir probes on pico-satellites flying in low Earth orbit over mid- to low-latitude geographic regions. Following chapters on the expected ionospheric conditions and an overview of Langmuir probe theory, a chapter addressing the difficulties involved with pico-satellite Langmuir probes is presented. Also, the necessary satellite-to-probe surface area requirements in order to achieve confidence in pico-satellite Langmuir probe data, for the orbital regions of interest to this thesis, are stated.