Ion-scale characteristics and dynamics of dayside magnetopause reconnection exhausts: Effects of interplanetary magnetic field orientation




Vines, Sarah K.

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Leading to vibrant aurorae and the potential for widespread satellite disruption, magnetic reconnection plays a vital role in the interaction between the solar wind and the magnetosphere of the Earth. The purpose of this dissertation is to investigate and determine how the conditions upstream of the Earth's magnetosphere influence the localized ion-scale characteristics of reconnection at the dayside magnetopause (MP). Observations from the Cluster and Magnetospheric Multiscale (MMS) missions are used to characterize ion populations and ion-scale dynamics of reconnection at the dayside MP. A large database of Cluster 3 MP crossings has been used to assess effects of interplanetary magnetic field (IMF) orientation on ion acceleration in reconnection exhausts. While there appears to be a slight dependence of ion acceleration on the IMF clock angle, the reconnection exhausts observed appear to be highly variable, and may have secondary dynamics, like multiple reconnection sites, affecting the ion acceleration. The same Cluster database has also been used to study effects of IMF orientation on the frequency and location of magnetic island formation. These structures are found across the dayside MP with nearly equal frequency for both anti-parallel and component reconnection, indicating that magnetic islands are a common feature of dayside reconnection sites. Finally, MMS observations are used to investigate heating of heavy ion species (He+, He 2+, and O+) at the MP during a particularly advantageous MP crossing. With the Hot Plasma Composition Analyzer (HPCA) on MMS, these heavier ions are tracked as they mix across the reconnection exhaust.


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Magnetic Reconnection, Magnetopause, Space Physics



Physics and Astronomy