Question: Must every magnetic configuration have a north and south pole?
Answer: Not necessarily. True only if the source of the field has a net non-zero magnetic moment. This is not so for a toroid or even for a straight infinite conductor.
(source: uni-wuppertal.de)
I understand that a straight infinite conductor will not experience a torque in a uniform magnetic field. It will only experience a net force based on its orientation. And so it doesn't have a net magnetic moment.
But I'm unable to visualize how a toroid will behave in a uniform external magnetic field. Since the answer to the above question says that a toroid doesn't have a magnetic dipole moment, I can conclude that it doesn't experience a torque. But does it experience a net force? Please explain how a toroid behaves in an external magnetic field at the basic level of each loop of wire.