Categorizing FTE-like Boundary Layer Signatures Produced by the Kelvin-Helmholtz Instability Using Hall-MHD Simulations and Virtual Spacecraft

Magnetic reconnection and Kelvin-Helmholtz instability (KHI) are two fundamental processes at the planetary magnetospheres that can lead to plasma, momentum and energy transport over magnetospheric boundary. Flux Transfer Events (FTEs) are generally accepted to be produced by the magnetic reconnection at the dayside magnetopause. However, there are still other possible mechanisms which create FTE-like features in the boundary layer. Kelvin-Helmholtz instability can be one of the candidates. The deformed boundary driven by the KHI at the interface of two fluids usually leads to the bipolar signatures of the normal component of the magnetic field. By using 2.5-dimensional Hall-MHD simulations, we study signatures observed by virtual satellites as they pass through KHI along different trajectories. For the same plasma parameters across the magnetosphere and magnetosheath, slightly adjusting the projection angle of the magnetic field will give us 12 combinations of in-plain components at both sides of the boundary. In addition, we assume 3 sets of spacecraft trajectories in each simulation, which totally bring 36 different KHI signatures. While the satellites encountered well-developed KH vortex and spine region, the signatures, when detected by a spacecraft in the magnetosphere, would be easily misidentified as FTEs. The presented analysis examines and categorizes these observed signatures that are clearly generated by the KHI. These results can be used as diagnostic when analyzing spacecraft data to help distinguish KHI created signatures from FTEs.