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 23 for “"Plasma Transport"”.
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Mathematical Modeling Plasma Transport in Tokamaks
… reactor (ITER) ignition studies. The multi-mode plasma transport model used here includes a linear combination of drift wave branch and ballooning branch instabilities with two a priori uncertain constants to account for anomalous plasma transport in tokamaks. A Bayesian parameter estimation …
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Numerical simulation of the Jovian torus-driven plasma transport
… The basic interchange instability of the Io plasma torus is opposed by pressure gradients in the energetic particles outside the torus. Many simulations have been performed for cases where the overall system is inter-change unstable under the ideal-MHD assumption E + v $\times$ B = 0. For …
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Three-dimensional modeling of plasma transport in the HIDRA stellarator
… experiments, the interactions between edge plasmas and the materials which ultimately confine them have become increasingly more important as device sizes and powers trend upwards. Devices such as MPEX and PISCES are built to investigate these interactions at the high energies and particle …
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Partially ionized plasma transport and line radiation interactions as the tokamak edge
… interacts with the high-density low-temperature plasma at the tokamak edge. As a result, there exists a significant nonlocal plasma energy transport channel, local atomic level populations are altered by global plasma properties, and plasma transport is affected. In this dissertation, new …
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Experimental study of plasma transport using X-ray imaging spectroscopy in Alcator C-Mod
… in the studies of impurity, momentum and energy transport in Alcator C-Mod. This thesis investigates three phenomena using HiReX-Sr: (1) Non-local heat transport (the breakdown of a local expression for the heat flux) is observed in linear Ohmic confinement (LOC) regime plasmas in cold pulse …
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Cleaning of tin debris by reactive ion etching in a discharge-produced EUV plasma source
… can be generated by making hot (Te ∼ 30 eV) plasma, and collected by optical mirrors in vacuum. During the light generation process, energetic ions or neutral debris are emitted from the plasma in addition to the desired light. The contamination by such debris will critically affect the life …
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Theoretical transport model for tokamaks
In the present thesis work a theoretical transport model is suggested to study the anomalous transport of plasma particles and energy across the axisymmetric equilibrium toroidal magnetic flux surfaces in tokamaks. The model suggests a linear combination of two transport mechanisms; drift waves, …
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Identifying Signatures of Plasma Waves and Reconnection Associated with Kelvin-Helmholtz Activity
… the shocked solar wind and magnetospheric plasma. Understanding the dynamics of the plasma processes at the magnetopause boundary is crucial to the study of plasma transport into the magnetosphere. Previous studies have shown that there exists a temperature asymmetry in the plasma sheet. …
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The Effects of Collisions on Plasma-Sheath Transition
The plasma sheath is essential for understanding the plasma-material interaction (PMI) since it regulates the plasma particle and energy fluxes to the wall. The key concept in sheath theory is the Bohm criterion that gives the lower bound of the plasma exit flow speed, also known as the Bohm speed. …
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Density structures in the Jovian magnetosphere
… resolution density data set derived from plasma wave instruments on board both Voyager 1 and Voyager 2. One hundred five structures are identified. They are believed to be the same type of structures as seen by Ansher et al. (1992) and are found to have sharp density gradients at the …
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Development of high energy pulsed plasma simulator for plasma-lithium trench experiment
… lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat …
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Experimental Studies of Neutral Particle Effects on Edge Transport Barriers in Tokamaks Using the Lyman-alpha Measurement Apparatus
… profile due to small spatial scales, complex plasma transport, and non-negligible effects of neutral particles. To better quantify the hydrogenic neutral particle source, a one-dimensional, absolutely calibrated pinhole camera system was installed on the DIII-D tokamak to measure edge …
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Finite drift orbit effects in a tokamak pedestal
… This region is characterized by a drastic plasma density drop over a relatively short radial distance, typically of order of the poloidal ion gyroradius (p,,). Experiments demonstrate that H Mode plasmas have superior transport properties compared to other known regimes, making them …
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Comparison of high power impulse magnetron sputtering and modulated pulsed power sputtering for interconnect metallization
… of barrier/seed layer deposition. Their plasma properties and metal ionization fractions are characterized using various pulsing and discharge parameters. Depositions on patterned wafers are performed to evaluate their potential for interconnect metallization application. Time- and …
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Probing the Quark-Gluon Plasma properties through Heavy Quarks' dynamics: transport coefficients and elliptic flow
… un nuovo stato di materia chiamato Quark-Gluon Plasma (QGP). Calcoli numerici basati sulla soluzione della QCD su reticolo (lQCD) hanno mostrato che questa transizione di fase è in realtà un crossover che si verifica ad una temperatura critica Tc=155 MeV. Lo studio della materia nucleare in …
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SUPPRESSION OF ELECTRON THERMAL CONDUCTION IN THE HIGH β INTRACLUSTER MEDIUM OF GALAXY CLUSTERS
… in a galaxy cluster requires a knowledge of the plasma transport processes, especially thermal conduction. The basic physics of thermal conduction in plasmas with ICM-like conditions has yet to be elucidated, however. We use particle-in-cell simulations and analytic models to explore the dynamics …
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MMS Observations of the Kelvin-Helmholtz Instability and Associated Ion Scale Waves
… 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 …
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A Continuum Kinetic Investigation into the Role of Transport Physics in the Bohm Speed formulation
When plasmas come in contact with the boundaries that confine them, various complex processes occur between the plasma and the materials in the boundary. These processes, called plasma-material interactions (PMI) lead to physical and chemical modifications in the materials and in the plasma. In the …
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Characterization of ion properties in a linear pulsed plasma-material interaction test stand
… divertor regions of the magnetically confined plasma, tokamaks experience off-normal events in which high intensities of heat flux incident on wall component surfaces result in intolerable levels of damage. Proposed solid divertors will not be able to withstand these fluxes, especially in …
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Understanding the Mechanisms that Determine the Edge Electron Density Profile in Tokamaks
The interaction between the physics of plasma turbulence and that of atomic neutral dynamics, intrinsic to the tokamak edge, makes prediction of edge profiles difficult. It is unclear to what extent neutral ionization, as opposed to particle transport, is responsible for the build up of edge …
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