Why do charged cosmic rays strike earth near poles more often than equator?

Question

I'm guessing this has to do with the magnetic field of the earth. But I cant find any more detail on it. Why does the magnetic field exert a magnetic force in the direction of the poles?

Answer 1

Short explanation without details. (I'm a Russian, so forgive me my rugged English).
Force lines of the Earth's magnetic field exit from the Earth's surface near magnetic poles (which are close to the geographic poles), then the lines disperse in all 360 deg directions and spread towards the opposite pole, simultaneously the lines go up to the atmosphere and nearby space. So, above major part of the Earth's surface the lines are directed almost along meridians, ascending up, if we move towards equator, and descending to the surface, if we move towards the poles.
When charged particles enter a magnetic field, they begin to coil along force lines (like if they move along a screw on it's threading, the screw is oriented along a force line). Above equator, magnetic force lines are almost parallel to the Earth's surface, so charged particles are catched and begin to move along force lines while descending towards the surface. In the areas around the poles they enter the atmosphere causing "nothern lights" (colliding with air molecules).

Answer 2

Because of the shape of the earth's magnetic field which is parallel with the surface at the equator and turns down to perpendicular at the north and south magnetic poles (like the layout of iron filings on paper over a bar magnet.