0.9 MEG AVI File or 3.0 MEG QuickTime File.

The field lines of a magnetic dipole for the case where the dipole moment rises from zero to a constant over a time scale T. The specific time dependence of the dipole moment is proportional to (Pi/2+arctan(t/T))/Pi, which is a function which is 0 at t = -infinity and 1 at t = + infinity, and increases in a characteristic time T.