  This work is based on a paper with Margaret James, to appear in Phys Rev D.
In it we showed that the dipole moment of the sphaleron has its origin in two
components: a ring of electric current circulating around the edge of the
sphaleron; and also two regions of opposite magnetic charge above and below the
ring. This magnetic charge has a partly topological explanation, arising from
the fact that the sphaleron is axisymmetric and parity invariant. Here, I
discuss the definition of the electromagnetic field and its sources in the
Standard Model, comparing the one we use with the better-known one of 't Hooft.
I also discuss the resemblance between the sphaleron and Nambu's ``dumb-bell''
-- a segment of $Z$-string which connects a monopole to an antimonopole.
