Flow Channel and Velocity Shear Impacts on the Thermoshperic CUSP, with Associated Neutral Upwelling

Abstract:

Magnetic reconnection-produced plasma flow channels form in the cusp region of the ionosphere typically near 75º magnetic latitude, and occur in all seasons and solar cycles. Flow channel lengths can be over 1000 km, with 1500-2000 km being a reasonable estimate, and with their widths typically being 1° - 3° in latitude. During active IMF Bz south conditions, flow channel velocities may exceed 1.3 km/s a third of the time, 2 km/s a sixth of the time, and reach 3 km/s a couple of percent of the time. In this general study, the various CUSP processes will be modelled simultaneously with the net outcome depending on several parameters, including the channel width, the location of the channel, the electric field and electron density profiles inside and outside of the channel, the lifetime of the event, and the background thermospheric conditions. Realistic channel drivers were used for this simulation, which were based on CUSP measurements, with the associated neutral thermospheric upwelling effects being assessed.