Effect of convection vortices on the ionosphere

Abstract

Traveling convection vortices are spatially localized, transient structures embedded in a large-scale convection pattern. They are typically aligned in the east-west direction, have a horizontal extent of 500–1000 km, appear in either the dawn or dusk sectors at about 70° latitude, and then propagate toward midnight at a speed of from 0.5–15 km/s. Associated with the convection vortices are a field-aligned current pair, particle precipitation and enhanced electric fields. In order to determine their effect on the polar ionosphere, the USU ionospheric model was used to calculate the ionospheric response to traveling twin vortices. Simulations were conducted for both summer and winter conditions and for different vortex characteristics, including both decaying and non-decaying vortices, slow and fast moving vortices, and a series of traveling vortices. The simulations indicate that there is an appreciable ionospheric response, but it varies markedly with altitude and the magnitude of the response depends on the vortex characteristics.