Formation of O$^{+}$ trough zones in the polar cap ionosphere-magnetosphere coupling region: Dynamic Fluid-Kinetic Simulations

Thermal ion measurements by the Thermal Ion Dynamics Experiment(TIDE) on the POLAR spacecraft show that the O$^{+}$ densities in the polar cap near 6000 km altitude display structured variations featuring low-density trough regions. For this presentation, the UT Arlington Dynamic Fluid-Kinetic (DyFK) model is utilized to investigate such O$^{+}$ density profiles. Using available measured solar wind parameters to drive a time-varying high-latitude convection model and incorporating auroral processes of soft electron precipitation and wave-driven ion heating, we simulate the evolving high-latitude ionospheric plasma transport and associated parameter profiles for several convecting flux tubes in the high-latitude ionosphere-magnetosphere system. The modeled densities near 6000 km altitudes are compared with multiple trough events featuring POLAR/TIDE-measured O$^{+}$ densities for inside and outside of such trough regions.