Excitation of Pseudowaves in a Plasma via a Grid

When a time-varying potential is placed on a grid located in a plasma, coherent bursts of charged particles having peak energies corresponding to the applied potential are emitted from the grid region. These ion bursts produce an ion-wavelike phenomenon, which is not predicted by the ordinary dispersion relation. We have observed these "pseudowaves" having wavelengths larger than the Debye radius, which suggests that in this case some cooperative electrostatic process must be present. These pseudo ion waves have been used as a tool to study plasma phenomena.