Vortical electromagnetic waves with a stationary power flow

We show analytically that in source free medium vertical electromagnetic wave can be derived from electromagnetic field, described by electric and magnetic Hertz vectors. To characterize the wave's vorticity we examine moment values of the real Poynting vector versus various directions of Hertz vectors in respect of wave propagation. This enables us to distinguish pure circular polarized transverse waves, possessing constant modulus orbital angular momentum and time and space invariant Poynting vector, from those of vortical, consisting of two time invariant and two vortical time dependent components. Poynting vectors of vortical components depend on time and have opposite directions while the time unvarying components have the same direction towards the wave propagation. The result of interaction of two vortical components is time invariant orbital angular momentum and time independent power flux, which is directed perpendicular to the common power flux of unvarying components.