Coupling of ionosphere plasma and neutral atmosphere in the ionospheric dynamo region

Abstract

The ionospheric dynamo/transition region at ~90-150 km altitude is determined by the collisionality of neutral atmosphere and ionosphere plasma. At these altitudes, the two gases undergo a transition from being highly collisional to non-collisional. Pedersen and Hall conductivities maximize in the dynamo region and their vertical profiles strongly depend on the coupling of neutral and plasma particles. Atmospheric processes in this region (e.g. tides, gravity waves, etc.) significantly impact the ionospheric variability. Combined observations of neutral atmosphere and ionosphere plasma in the transition region are essential to understand these processes and the plasma-neutral coupling. Incoherent Scatter Radars (ISR) are capable to measure basic plasma parameters across the whole dynamo region and also allow us to infer information about the neutral atmosphere under certain assumptions. We present combined measurements of atmosphere-ionosphere coupling processes in the transition region with the EISCAT ISR located in Northern Scandinavia and other instruments in the area. Such measurements can be applied to assess the ionospheric variability caused by atmospheric processes like the mixing of tidal modes or atmospheric gravity waves. The possibility to infer additional atmosphere-ionosphere parameters is demonstrated as well