To illustrate the concept of the dynamic creation of static fields, the fields associated with the creation of a static point charge and a static point dipole between times t=0 and t=tau are calculated. For the former the field is that of a static charge in all space once t >tau. For the static point dipole the field pattern consists of three zones once t >tau. An expanding sphere of radius r=c(t-tau) in which the field is that of a static dipole, a shell defined by c(t-tau)ct, for which the fields vanish. Despite the fact that the electric field occupies an increasing volume in space with increasing time, the energy in the field is constant once the dipole has been created. This result is established explicitly for an arbitrary creation of the static dipole. (C) 2008 American Association of Physics Teachers.
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