A simulation study on the relationship between field-aligned and field-perpendicular plasma velocities in the ionospheric F region

The anticorrelation between the diurnal variations of V-i parallel to and V-i perpendicular to N is associated with the neutral wind dynamo. Poleward meridional winds result in downward V-i parallel to and poleward V-i perpendicular to N, and vice versa. The anticorrelation between short-term temporal disturbances of V-i parallel to and V-i perpendicular to N is mainly caused by ion drag, in response to high-latitude convection electric field forcing.

This forcing penetrates to lower latitudes and affects poleward plasma drifts V-i perpendicular to N, which drags poleward meridional winds and modulates downward V-i parallel to. As the enhanced convection electric fields subside, the anticorrelation is mainly associated with disturbance meridional wind dynamo. The storm time high-latitude energy and momentum inputs change global meridional winds which modify zonal electric fields to induce V-i perpendicular to N changes.

Furthermore, ambipolar diffusion plays a significant role in modulating the relationship between V-i parallel to and V-i perpendicular to N.