Mapping of ionospheric outflows into the magnetosphere for varying IMF conditions

The presence of different ion species and components provides important insight into the processes that determine the entry, transport and acceleration of plasma within the magnetosphere. Multi-fluid simulations that include both ionospheric H+ and O+ and solar wind H+ are used to evaluate the ionospheric outflows in response to a range of solar wind conditions. O+ is particularly important as its provides a definitive means for determining the influence of ionospheric ions in the magnetosphere. While O+ is gravitationally bound to the earth during quiet periods, enhancements in the cross-polar cap potential during southward IMF can produce centrifugal acceleration of the O+ to produce enhanced outflows. However the same strong convective electric field causes much of this O+ to be confined to the inner magnetosphere. During subsequent northward turning of the IMF, this ionospheric-rich plasma is ejected down the length of the deep tail. The derived O+ density for this combination of alternate southward and northward IMF produces concentrations similar to those observed by Geotail, (C) 2000 Elsevier Science Ltd. All rights reserved.