This chapter begins by expressing the multipole expansion of the dynamic vector potential A
(
r, t) in terms of electric and magnetic multipole moments. Differentiation of A
(
r, t) leads directly to the fields E
(
r, t) and B
(
r, t), which have a component transporting energy away from the sources to infinity. This component is called electromagnetic radiation and it arises only when electric charges experience an acceleration. A range of questions deal with the various types of radiation, including electric dipole and magnetic dipole–electric quadrupole. Larmor’s formula is applied in both its non-relativistic and relativistic forms. Also considered are some applications involving antennas, antenna arrays and the scattering of radiation by a free electron.
Pulsar Spin-Down by 3P2 Superfluid Neutrons