# Illustration Harmonic plane wave (1d) - Propagation

A one-dimensional harmonic plane wave $$\mathit{\Psi}(x,t)$$ propagating to the right:$$\mathit{\Psi}(x,t) ~=~ A \, \cos(k\,x - \omega \, t)$$where $$A$$ is the amplitude, $$k$$ is the wave number and $$\omega$$ is the frequency of the wave.
The wave at the time $$t = 0$$ and at a later time $$t$$.