Plasma density features associated with strong convection in the winter high‐latitude F region

Abstract

We combined a simple plasma convection model with an ionospheric‐atmospheric composition model in order to study the plasma density features associated with strong convection in the winter high‐latitude F region. Our numerical study produced time‐dependent, three‐dimensional, ion density distributions for the ions NO+, O2+, N2+, O+, N+, and He+. We covered the high‐latitude ionosphere above 42° N magnetic latitude and at altitudes between 160 and 800 km for a time period of one complete day. From our study, we found the following: (1) For strong convection, the electron density exhibits a significant variation with altitude, latitude, longitude, and universal time. A similar result was obtained in our previous study dealing with a weak convection model. (2) For strong convection, ionospheric features, such as the main trough, the aurorally produced ionization peaks, the polar hole, and the tongue of ionization, are evident but they are modified in comparison with those found for slow convection. (3) For strong convection, the tongue of ionization is much more pronounced than for weak convection. (4) The polar hole that is associated with quiet geomagnetic activity conditions does not form when the plasma convection is strong. (5) For strong convection, a new polar hole appears in the polar cap at certain universal times. This new polar hole is associated with large downward, electrodynamic plasma drifts. (6) For strong convection, the main or mid‐latitude electron density trough is not as deep as that found for a weak convection model. However, it is still strongly UT dependent. (7) The ionospheric parameters NmF2, hmF2, and the topside plasma density scale height exhibit an appreciable variation over the polar region at a given UT.