Example 2.1

Composition of progressive waves radiated from two sources at distance d.

Wave sources are represented by black dots. The left source located at $z = -d$ radiating progressive waves $\psi_1$ is shown in the upper graph. The right source at $z=d$ radiating wave $\psi_2$ is shown in the lower graph. The superposition of these waves, $\psi = \psi_1 + \psi_2$, is shown in the middle graph:

Source code: nb (here the animation is interactive with the possibility to change the distance of sources and thus observe the change in interference (constructive vs. destructive))