A circular coil carrying current behaves as a

A magnetic shell is a thin sheet of magnetic material of uniform thickness magnetized at every point in a direction perpendicular to the surface of sheet.

The lines of forces drawn outside a circular coil carrying current are continuous as loops throughout giving rise to a shape of magnetic shell and they do not move from one end to the other end to form a shape that is similar to bar magnet, horse shoe magnet or a solenoid.