If it weren’t for the Earth’s magnetic field we would be subject to bursts of radiation on the ground that would be, at the very least, unhealthy. If the magnetic field stays the same, then eventually the ion will be pulled in a complete circle. The Earth’s magnetic field points from south to north through the Earth’s core, then curves around and points from north to south on Earth’s surface and out into space. If a charge moves in the direction of a magnetic field, not across it, then it’s not pushed around at all. The Earth’s magnetic field does more than just deflect ions or direct them to the poles.