Back to Maxwell animations home page
Dielectric constant distribution
|When there are fluctuations in refractive index on the scale of half the wavelength of the radiation, then the scattered waves constructively interfere in the backward direction (note that the apparent scattered wave travelling in the forward direction in this example is simply the energy extracted from the incident wave. This is how clear-air radars work, for which it is known (somewhat misleadingly) as Bragg scattering. Now see what happens when the fluctuations in refractive index have the same scale as the wavelength.|
This is an animation of the component of the electric field out of the plane of the page.
The direction in which energy is travelling at any instant is proportional to the cross product of the electric and magnetic fields, known as the Poynting vector. The arrows show the direction of the Poynting vector averaged over the simulation, while the colours show its strength.