Reflection of ion-acoustic waves from an ion sheath at a grid

The reflection of continuous sinusoidal waves from a grid is investigated experimentally. It is found that the reflection coefficient has a distinct maximum in contrast to the prediction of the theory. The electron components of the incident and reflected waves are observed to vanish within the quasineutral layer close to the grid where the plasma density rapidly drops. Furthermore it is shown that the reflected wave is a downstream wave that propagates on the ion beam that originates on the other side of the grid.