Effects of Magnetic Reconnection Dynamics in Earth's Cusp: Investigating Plasma Filaments and Flux Transfer Events using MMS Data

Energetic particles injected from dayside reconnection serve as a source for ionospheric particle precipitation in the cusp region. The cusp comprises poleward-moving plasma structures, cusp plasma filaments due to discontinuous reconnection events which are considered footprints of flux transfer events (FTEs). These structures remain relatively unexplored on Earth, however an examination of MESSENGER data from Mercury's magnetosphere suggests that cusp filaments represent the magnetospheric extensions of FTEs originating at the magnetopause due to localized magnetic reconnection. This underscores the need for a comprehensive investigation of similar phenomena within Earth's magnetosphere. Reconnection often takes place at the dayside magnetopause, where the solar wind's magnetic field interacts with the Earth's magnetic field. This interaction leads to the merging and rearrangement of magnetic field lines, creating open magnetic field lines that connect the high-latitude magnetospheric cusp to the solar wind forming FTEs which are flux-rope-like structures filled with magnetosheath plasma. In this study, data obtained from the MMS spacecraft was examined which is strategically positioned to traverse the cusp region. The spacecraft's orbit facilitates multi-spacecraft in situ measurements within the cusp, providing crucial data for the analysis of phenomena such as cusp plasma filaments. Cusp filaments were analyzed using multi-spacecraft analysis techniques and high-resolution measurements were utilized to reconstruct and analyze the internal plasma structure of these cusp filaments. Characteristics and spatial distribution of cusp plasma filaments within Earth's cusp region were also investigated. The primary focus was to comprehend the role of these filaments in particle precipitation and their correlation with dayside magnetic reconnection events. Our preliminary results suggest that cusp plasma filaments are indeed low latitude, high altitude footprints of FTEs. Moreover, there appears to be a correlation between the presence of plasma filaments and dayside reconnection events.