Fountain-like flow of heavy oxygen ions from the Earth's ionosphere in response to transverse heating

Normally, the gravitationally bound heavy O/sup +/ ions in the Earth's ionosphere are in a diffusive equilibrium. However, when energized to superthermal energies of a few electron volts transverse to the geomagnetic field, the combined effects of the downward gravitational and the upward electric and mirror forces produce interesting flow patterns in the vertical direction, as in a pulsating fountain. This flow pattern is studied by means of a particle-in-cell code.