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dc.contributor.advisorKim Molvig.en_US
dc.contributor.authorCottrill, Larissa Aen_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.en_US
dc.date.accessioned2010-03-25T15:22:44Z
dc.date.available2010-03-25T15:22:44Z
dc.date.copyright2009en_US
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/53262
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2009.en_US
dc.descriptionCataloged from PDF version of thesis.en_US
dc.descriptionIncludes bibliographical references (p. 179-183).en_US
dc.description.abstractA crucial issue surrounding the feasibility of fast ignition, an alternative inertial confinement fusion scheme, is the ability to efficiently couple energy from an incident short-pulse laser to a high-density, pre-compressed fuel core. Energy transfer will involve the generation and transport of a relativistic electron beam, which may be subject to a number of instabilities such as the two-stream, Weibel, and filamentary instabilities that act to inhibit energy transport. This research addressed these issues by investigating the three main phases of the electron transport process: hot electron generation in the cone and the extent of confinement along the cone surface, linear instability growth in the outer plasma corona, and the nonlinear saturated state in the inner plasma corona. Analytical and computational models were constructed to include relevant physics that had been excluded from previous models, such as kinetic and collisional effects, and included use of a sophisticated particle-in-cell code (LSP). During the initial phase of transport, our simulation results showed that contrary to experimental claims, hot electron surface confinement is only a minor effect and the cone target angle is a minimal concern for design considerations. The discrepancy was attributed to a phenomenon known as escaping electrons and the enhanced intensity of electrons measured along the surface was attributed to target geometry, rather than surface confinement.en_US
dc.description.abstract(cont.) The second phase of transport was modeled analytically with the Vlasov-Krook-Maxwell formulation, which included collisional effects, various assumed theoretical distributions, and a data fit obtained from a simulation of the laser-plasma interaction. Our primary results indicated that collisions generally suppress growth but do tend to enhance filamentary instability growth at some wavelengths; however, due to the large temperature of the data fit, the overall growth rates are relatively small for fast ignition considerations. Analysis of the saturated regime, including particle orbits, revealed similar conclusions that instabilities can be safely neglected for fast ignition conditions, especially in the high density region of the fuel, which would otherwise need to resolved at great computational expense.en_US
dc.description.statementofresponsibilityby Larissa A. Cottrill.en_US
dc.format.extent183 p.en_US
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582en_US
dc.subjectNuclear Science and Engineering.en_US
dc.titleRelativistic electron beam transport for fast ignition relevant scenariosen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Nuclear Science and Engineering
dc.identifier.oclc540833878en_US


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