The earth has a magnetic field too.  Its magnetic field is shaped by the pressures of the solar wind.  If the earth's magnetic field was not affected by the solar wind, then it would look symmetrical, like the field of a simple dipole bar magnet (below).
	The earth's magnetic field works the same way a bar magnet  does.  Near the north and south poles the magnetic field lines are close together.  This is where the magnetic field is strongest.  Where the magnetic field lines are far apart, the magnetic field is the weakest.