Question #657d6

1 Answer
Oct 27, 2015

The magnetic field is given by the curl of the vector potential, #A#.

#B=\nabla\times A#

Explanation:

The vector potential , #A# , is used because it often provides an easier way to find #B#.

It is analogous to how the electric field, #E#, can be derived from the scalar potential #V#. #\quad \quad\quadE=\nabla V#

#A# can be calculated by:

#A=\mu_0/{4\pi}\intJ_{(r)}/{r-r_0}dV#

where #J# is the current density at the point #r#. This expression comes from the Helmholtz Theorem.