The quasistatic approximation implies that the equation of continuity can be written as ∇ ⋅ J = 0 and that the time derivative of the electric displacement
∂D/∂t can be disregarded in Maxwell–Ampère’s law.
There are also effects of the motion of the geometries. Consider a geometry moving with velocity v relative to the reference system. The force per unit charge,
F/q, is then given by the
Lorentz force equation:
where Je is an externally generated current density.