Effects of geographic‐geomagnetic pole offset on ionospheric outflow: Can the ionosphere wag the magnetospheric tail?

Abstract

The generalized polar wind model was used to simulate the polar ionosphere during the September/October 2002 storm. The solar terminator moved across the polar caps in a diurnal oscillation during this equinox period. The main conclusions of this study are the following: (1) the terminator oscillation generates a diurnal oscillation in the total hemispheric fluxes of the polar wind from the ionosphere into the magnetosphere; (2) the diurnal oscillation of outflow in the Northern Hemisphere is 12 h out of phase with the Southern Hemisphere; (3) the H+ outflow flux is near its limiting value, so the oscillation is larger than the nonperiodic contributions (e.g., geomagnetic activity); and (4) the O+ flux is less than its limiting value, hence the diurnal oscillation is comparable to the non-periodic effects. The simulation suggests that the hemispherical asymmetry and periodicity of the total ion outflow could “wag the magnetospheric tail” and perhaps contribute to substorm triggering.