Molecular ion upflow in the cleft ion fountain

Although the ionosphere is a continuous emitter of escaping light ions (Hand He+) and in the auroral zone a continuous emitter of escaping heavy ato mic ions (O+ and N+), it only sporadically emits molecular ions. This is du e to the significant gravitation barrier to their outflow and to the chemic al barrier created by their short life times against loss to dissociative r ecombination in the F region. The outflow of molecular ions requires a spec ial set of circumstances. In this paper we present evidence that one ingred ient for those special circumstances is the presence, in the ionosphere, of a strong convection electric field. This can occur in various places near the auroral zone, in nightside subauroral ion drift events, and in the cusp . We show several examples of Dynamics Explorer (DE) 1 and 2 near-conjuncti on data in which molecular ions are seen at high altitude (1400-4000 km) by DE 1 near where DE 2 sees strong cusp associated plasma convection and ion ospheric and thermospheric modification.