The sinusoidal form of the magnetic field is defined as:

(33–1)

where is the mean vector, is the amplitude vector, is defined as the propagation vector, is the position vector of an arbitrary point. , and are the , and direction cosines respectively. The quantities , , and are the frequency, wavelength, and phase offset, respectively. For a non-moving field, the propagation vector is zero.

The square form of the magnetic field is defined as:

(33–2)

The definition of the propagation vector is the same as for the sinusoidal form.