This Demonstration shows the quantitative magnetic field and magnetic induction for a cylindrical bar magnet. The magnetization
is assumed to be in the
direction and uniform within a magnet of diameter
. Colors on a logarithmic scale show field intensity and arrows show its direction. The field
outside the magnet satisfy
, so the field patterns are identical (the same color is used for both fields). They are different inside the magnet, since there
vectors go from the north pole to the south pole (top to bottom) in all regions,
vectors return to the north pole through the magnetized body.