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The Plasma Physics Processes that Drive Ring Current Enhancements during Geomagnetic Storms and Substorms

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dc.contributor.advisor Winglee, Robert M en_US Cash, Michele en_US 2012-09-13T17:33:39Z 2012-09-13T17:33:39Z 2012-09-13 2012 en_US
dc.identifier.other Cash_washington_0250E_10096.pdf en_US
dc.description Thesis (Ph.D.)--University of Washington, 2012 en_US
dc.description.abstract Geomagnetic storms result when energetic particles of solar and ionospheric origin fill Earth's inner magnetosphere and create a strong westward current, known as the ring current. This dissertation presents results from investigating the plasma dynamics that contribute to the development of Earth's ring current from ionospheric outflow of H+ and O+ ions, and the role of ring current enhancements in the generation of geomagnetic storms and substorms. Modeling was carried via a combined multifluid and particle approach, which enables us to resolve the small-scale dynamics that are key to particle energization within the context of the global magnetosphere. The results presented in this dissertation substantially contribute to our understanding of the development and composition of the ring current during geomagnetic storms and substorms, and offer insight into the ionospheric sources regions for ring current ions, as well as the processes through which these particles are energized, injected, and trapped within the inner magnetosphere. This thesis presents results that show how small-scale particle dynamics within the current sheet, boundary layers, and reconnection regions drive the acceleration of ring current particles within the larger global context of the magnetosphere. Small-scale structures within the magnetotail are shown to be more important in determining when particles are accelerated than the time after particles are initialized in the ionosphere. It is also found that after a period of southward IMF, in which particle energization is observed, a northerly turning of the IMF is necessary in order to trap energetic particles in orbit around the Earth and form a symmetric ring current. Asymmetries in the acceleration mechanisms between ionospheric H+ and O+ ions were observed with oxygen ions convecting duskward according to the cross-tail current and gaining more energy than protons, which moved earthward on reconnecting field lines and were accelerated closer to the plasma sheet inner boundary. en_US
dc.format.mimetype application/pdf en_US
dc.language.iso en_US en_US
dc.rights Copyright is held by the individual authors. en_US
dc.subject Geomagnetic Storms; Radiation Belts; Ring Current en_US
dc.subject.other Plasma physics en_US
dc.subject.other Earth and space sciences en_US
dc.title The Plasma Physics Processes that Drive Ring Current Enhancements during Geomagnetic Storms and Substorms en_US
dc.type Thesis en_US
dc.embargo.terms No embargo en_US

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