Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"Plasma Instabilities"”.
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Third-order theory of pump-driven plasma instabilities : laser-pellet interactions.
Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
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Examining Plasma Instabilities as Ionospheric Turbulence Generation Mechanisms Using Pseudo-Spectral Methods
… model to study the effect of the eclipse on the plasma density. The calculated GDI growth rates are small compared to how quickly the eclipse moves over the Earth. Therefore, the GDI is not expected to occur during the solar eclipse. A novel 2D electrostatic pseudo-spectral fluid model is …
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Data-driven study of major disruption prediction and plasma instabilities across multiple tokamaks
… Along the way, scientists need to learn to avoid plasma disruptions: these sudden and unexpected plasma terminations still represent one of the key challenges for tokamak devices. Forecasting plasma instabilities and disruptions using first-principle models has been demonstrated to be extremely …
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Modeling of Polar Cap Ionospheric Patches and Attendant Plasma Instabilities: Initialization from Data and Parametric Analysis
… history of theoretical work on ionospheric plasma patches and their attendant plasma fluid irregularities, particularly within the polar cap region. Within this region though, plasma theory does not always yield tractable problems with succinct analytic solutions that are conceptually …
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Nonlinear oscillations in high power systems
… electronics and systems/devices used to sustain plasma fusion. Although it is common that System Engineers tend to associate high power systems with power electronics, it is worth noting that power systems related to nuclear fusion represent a challenging area rich in nonlinearities. …
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Design and Characterization of a Coaxial Plasma Railgun for Jet Collision Experiments
Plasma railguns are electromagnetic accelerators used to produce controlled high velocity plasma jets. This thesis discusses the design and characterization of a small coaxial plasma railgun intended to accelerate argon-helium plasma jets. The railgun will be used for the study of plasma shocks in …
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Orbital Debris Removal Technologies: A Hybrid Electrodynamic Tether and Ion Beam Shepherd Satellite Design for Fuel Efficient Contactless Debris Removal
… debris pieces within 200 days. Possible ion-beam plasma instabilities are hypothesized, but not investigated and are recommended for further research. A full systems analysis is recommended to determine a feasible dry mass, which can then lead to more accurate simulation results.</p>
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Numerical Simulation of Ion Waves in Dusty Plasmas
… of electrostatic and electromagnetic waves and instabilities in dusty plasmas. Dusty plasmas are characterized by the presence of micrometer or submicrometer size dust grains immersed in a partially or fully ionized plasma. In this study, a two-dimensional numerical model is presented to study …
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Design of control electronics for the Ram Energy Distribution Detector
… an important factor in predicting the onset of plasma instabilities that are known to distort and/or disrupt high frequency radio communications. A ram wind sensor is a space science instrument that, when mounted on a satellite in low-Earth orbit, makes in-situ measurements of the component of …
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The Effects of Weak Collisions on Nonlinear Plasma Kinetics
<p>Kinetic plasma behaviors have long been of interest to those studying space and laboratory plasmas. For instance, kinetic plasma instabilities are widely believed to be responsible for the generation of anomalous resistivity in reconnection layers, providing a possible mechanism for fast …
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A study of stimulated Brillouin scattering in laser produced plasmas
… nuclear fusion. The exploitation of laser-plasma instabilities, in particular stimulated Brillouin scattering (SBS), for the creation of such pulses is found to have great potential. Analysis from numerical, analytical and experimental studies are presented within this thesis which were …
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Investigation of triggering mechanism of internal transport barriers on the Alcator C-Mod tokamak using Thomson scattering diagnostic
Internal transport barriers (ITBs) in tokamak plasmas are characterized by the reduction of transport in one or more of the particle, momentum, or energy channels in the core plasma region. On Alcator C-Mod, significant contributions to ITB studies were made possible with the core Thomson …
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H (sub) alpha & Neutral Density Scaling in the Maryland Centrifugal eXperiment
… Centrifugal eXperiment (MCX) is a hydrogen plasma confinement experiment with a rotating mirror magnetic configuration. This experiment was designed to test the concepts of centrifugal confinement and velocity shear stabilization which may allow scaleability to a fusion reactor. These two …
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Next Generation Algorithms for Magnetically Confined Fusion Reactor Simulations
… non-linear MHD (magnetohydrodynamics) plasma instabilities and disruption events. The objective is to model all reactor regions (plasma, quasi-vacuum, and containment vessel) within a single three-dimensional simulation on a Cartesian reference frame, diverging from traditional …
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Modeling of Plasma Irregularities Associated with Artificially Created Dusty Plasmas in the Near-Earth Space Environment
Plasma turbulence associated with the creation of an artificial dust layer in the earth's ionosphere is investigated. The Charged Aerosol Release Experiment (CARE) aims to understand the mechanisms for enhanced radar scatter from plasma irregularities embedded in dusty plasmas in space. Plasma …
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Nonlinear Evolution of Mirror Instability in the Earth's Magnetosheath in PIC Simulations
… magnetosheath and they are generated in space plasma environments with proton temperature anisotropy of larger than one. The proton temperature anisotropy also drives the proton cyclotron instability which has larger linear growth rate than that of the mirror instability. Linear dispersion …
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Response Of Plasma Facing Components In Tokamaks Due To Intense Energy Deposition Using Particle-In-Cell(pic) Methods
<p>Damage to plasma-facing components (PFC) due to various plasma instabilities is still a major concern for the successful development of fusion energy and represents a significant research obstacle in the community. It is of great importance to fully understand the behavior and lifetime …
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Study of waves observed in the equatorial ionospheric valley region using Jicamarca ISR and VIPIR ionosonde
… density gradients that could be a source of plasma instabilities. Still, density variations across the magnetized plasma in the region can be key to explaining the enhanced echoes observed via the electrodynamics that they can drive. We also found that there exist sub-minute quasi-periodic …
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Formation of small-scale irregularities in the auroral E region
… Farley-Buneman (F-B) and gradient drift (G-D) plasma instabilities is considered. A general 2-D dispersion equation is derived and analyzed. Then, a review of existing nonlinear theories is given. The thrust is on the theory predictions with respect to the phase velocity of plasma waves. As an …
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Continuum Kinetic Simulations of Plasma Sheaths and Instabilities
A careful study of plasma-material interactions is essential to understand and improve the operation of devices where plasma contacts a wall such as plasma thrusters, fusion devices, spacecraft-environment interactions, to name a few. This work aims to advance our understanding of fundamental …
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