Compute peak time for a plane wave in a homogeneous electromagnetic media.

For a particular distance along the propagation path of a planewave in a homogeneous media, the peak time is the time at which the maximum signal amplitude is observed. In other words, it is simple computation for when the peak of the planewave will arrive.

For the quasistatic case (no electric displacement), the peak time is given by:

\[t_{max} = \frac{\mu \sigma z^2}{6}\]

where \(\mu\) is the magnetic permeability, \(\sigma\) is the electrical conductivity and z is the propagation distance.

zfloat or numpy.ndarray

propagation distance from the planewave source (m)

float, np.ndarray

Peak time/times in seconds