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dc.contributor.advisorMin-Chang Lee.en_US
dc.contributor.authorCohen, Joel (Joel A.)en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.en_US
dc.coverage.spatialn-us-aken_US
dc.date.accessioned2010-03-25T15:25:11Z
dc.date.available2010-03-25T15:25:11Z
dc.date.copyright2009en_US
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/53280
dc.descriptionThesis (S.M.)--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. 47-48).en_US
dc.description.abstractTwo research subjects: (1) excitation of "forced ion acoustic waves", and (2) "simultaneous excitation of plasma density fluctuations and geomagnetic field fluctuations" are reported in my M.S. thesis. The data was acquired in our experiments conducted at Gakona, Alaska from summer 2007 to winter 2008, using DoD/NSF-funded HAARP facilities and our own optical (ASIS) and radio instruments (VLF receiving system of IRIS) aided by GPS satellites as well as AMISR radar at Poker Flat, Alaska. We suggest that "Forced ion acoustic waves" detected by MUIR radar on Oct. 29 during 6:20-6:30 UT arise from keV electron precipitation associated with the occurrence of green aurora. Our work shows, for the first time, that MUIR radar is suitable for probing naturally occurring space plasma processes and not limited to HF heater-induced effects. This would extend the usage of MUIR for the investigation of space weather together with AMISR radar at Poker Flat, to advance our knowledge in space plasma turbulence. The research on "simultaneous excitation of plasma density fluctuations and geomagnetic field fluctuations" is an extension of my B.S. thesis research on thermal filamentation instability, which started in our summer Gakona experiments in 2005. Large plasma sheets (also known as sheet-like filaments) can be excited by HF O-mode and X-mode heater waves via thermal filamentation instability.en_US
dc.description.abstract(cont.) The dominant nonlinearity is provided by the differential Joule heating acting on electrons, which subsequently gives rise to a cross-field thermal pressure force, to concomitantly generate spatially varying plasma density fluctuations and geomagnetic field fluctuations. It is interesting to find that the fractional density fluctuations are approximately equal to the fractional magnetic field fluctuations. This gives us the theoretical basis to use ground-based magnetometer measurements to infer the density fluctuations in space plasma turbulence. Such a remote sensing technique for probing the space plasma is much more effective and economic than using a beacon satellite.en_US
dc.description.statementofresponsibilityby Joel Cohen.en_US
dc.format.extent77 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.titleExcitation of forced ion acoustic waves, large plasma sheets, and magnetic field fluctuations over Gakona, Alaskaen_US
dc.typeThesisen_US
dc.description.degreeS.M.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.en_US
dc.identifier.oclc547364516en_US


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