  Maxwell's equations and the equations governing charged particle dynamics are
presented for a rotating coordinate system with the global time coordinate of
an observer on the rotational axis. Special care is taken in defining the
relevant entities in these equations. Ambiguities in the definitions of the
electromagnetic fields are pointed out, and in fact are shown to be essential
in such a system of coordinates. The Lorentz force is found to have an extra
term in this frame, which has its origins in relativistic mass. A related term
in the energy equation, which allows inertia to be gained even during strict
corotation, suggests ways existing pulsar magnetosphere models may be modified
to match observed `braking indices' more closely.
