Up in the atmosphere of Earth, there are He2+ ions moving northwards and O−2 ions moving southwards. The concentration and speed for the He2+ ions are 2.8e12 m−3 and 2.0e6 m.s−1, while for the O−2 ions they are 7.0e11 m−3 and 7.2e6 m.s−1. Therefore, what will the direction and magnitude of the net current through a unit area be?