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dc.contributor.authorLindle, Molly Eileenen_US
dc.date.accessioned2012-06-06T16:49:04Z
dc.date.available2012-06-06T16:49:04Z
dc.date.issued2011-04-05en_US
dc.identifier.urihttp://hdl.handle.net/1853/43726
dc.description.abstractVolcanogenic lightning has a long documented history in the scientific field, though its origins are still poorly understood. The interactions leading to electrification of ash plumes is essentially a function of the microphysics controlling and affecting ash particle collisions. This thesis presents measurements made on charged particle interactions in a fluidized bed, with large-scale applications to the phenomenon of volcanogenic lightning and charged particle dynamics in volcanic plumes. Using a fluidized bed of ash samples taken from Ecuador's Volcán Tungurahua, particles are introduced to a collisional environment, where they acquire an associated polarity. A charged copper plate is used to collect particles of a given polarity, and particle size distributions are obtained for different weight fractions of the ash. It is observed that relatively smaller particles acquire a net negative charge, while larger particles in the sample charge positively. This is a well-documented occurrence with perfectly spherical, chemically identical samples, but this work represents one of the first applications of the principle to volcanic ash. Image analysis is preformed to determine the size distribution associated with specific polarities, and the associated minimum charge on each particle is calculated based on the plate collection height and particle size. We also present results that demonstrate the relationship between particle collisions and the amount of charge exchanged. Using techniques developed to examine the collision rate within a flow, combined with the charging rates determined from this experiment, we determine a maximum charge exchange rate of 1.28±0.23 electrons transferred per collision.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectVolcanicen_US
dc.subjectPlumeen_US
dc.subjectAshen_US
dc.subjectCharge exchangeen_US
dc.subjectChargeen_US
dc.subjectTriboelectricen_US
dc.subjectParticle size distributionen_US
dc.subject.lcshVolcanic plumes
dc.subject.lcshVolcanic eruptions
dc.subject.lcshParticle collisions (Nuclear physics)
dc.subject.lcshDynamics of a particle
dc.titleContact electrification and charge separation in volcanic plumesen_US
dc.typeThesisen_US
dc.description.degreeMSen_US
dc.contributor.departmentEarth and Atmospheric Sciencesen_US
dc.description.advisorCommittee Chair: Dufek, Josef; Committee Member: Bergin, Mike; Committee Member: Paty, Carolen_US


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