This project will use a variety of ground-based and space-based observations to examine the dynamics of the ionospheric trough during magnetic substorms. The high and mid-latitude, ionospheric troughs are regions of unusually low plasma density. The project will use observations from the Super Dual Auroral Radar Network (SuperDARN) coherent scatter radars, the Poker Flat Incoherent Scatter Radar (PFISR), and the all-sky imager and magnetometer arrays set up for NASA's THEMIS mission. It will utilize measurements of field-aligned currents (FACs) derived from the Iridium satellite network (the NSF supported AMPERE project). Three specific scientific topics will be addressed: (1) How does the mid-latitude trough evolve during substorms? (2) How is the high-latitude trough formed and why is it typically located immediately eastward of the Harang discontinuity? (3) What role do ionospheric conductances play in the discrepancy between the electric field and magnetic field Harang reversals.
The large-scale variations in the plasma density at mid and high-latitudes play an important role in the formation of smaller-scale plasma irregularities that affect communications and navigation. This project will examine the driving mechanisms that produce the large-scale variations during magnetically disturbed times. The work will improve our ability to understand and predict important space weather phenomena.