ECE PhD Prospectus Defense: Wei Zhang

Title: Structure and Evolution of Dayside Pc5 waves and Plasma Convection

Presenter: Wei Zhang

Advisor: Professor Toshi Nishimura

Chair: Professor Min-Chang Lee

Committee: Professor Toshi Nishimura, Professor Joshua Semeter, Professor Min-Chang Lee.

Abstract: The solar wind energy is transferred to the magnetosphere-ionosphere system through the magnetopause. Pc5 ultralow frequency waves transfer electromagnetic energy between the magnetosphere and ionosphere and they are important for particle acceleration and energy dissipation. However, it is generally difficult to discern the source region and the signal propagation path. The magnetic reconnection represents the major energy transfer process. It has been difficult to test the theories of reconnection X-line evolution due to the limited coverage by a small number of satellites. To address those issues, we propose to (1) identify the structure and propagation of Pc5 waves event using space-ground conjunction and (2) to determine the evolution of dayside plasma flows in the high-latitude ionosphere at both large and meso-scales associated with the interplanetary magnetic field (IMF) changes and to examine the corresponding dayside magnetopause reconnection process. The Pc5 event was identified as drift-mirror mode waves in the magnetosphere, which were driven by the magnetopause surface waves. For the dayside plasma flow enhancement, our preliminary results show that its azimuthal expansion during the IMF southward turning may have the IMF By dependence. We also determine the properties of multiple flow channels during the quasi-steadily southward IMF. We will investigate the dominant mechanism of dayside magnetopause X-line azimuthal spreading and the properties of the multiple magnetopause X-lines. The outcome of the proposed project will significantly advance our understanding of the solar wind-magnetosphere-ionosphere coupling from the perspectives of Pc5 waves propagation and reconnection-driven plasma flows.