  In an isotropic, homogeneous, nondissipative, dielectric-magnetic medium that
is simply moving with respect to an inertial reference frame, planewave
solutions of the Maxwell curl postulates can be such that the phase velocity
and the time-averaged Poynting vector are mutually orthogonal.
Orthogonal-phase-velocity propagation thus adds to the conventional
positive-phase-velocity propagation and the recently discovered
negative-phase-velocity propagation that is associated with the phenomenon of
negative refraction.
