An experimental search for theoretically predicted plasma wave instabilities in devices consisting of a superconducting layer of YBCO separated from a superconducting layer of niobium by a thin insulating layer is proposed. Theoretical work has shown that when the relative drift velocity between the parallel superconducting layers is large, an amplified plasma mode may exist, and can lose energy by electromagnetic radiation. This effect is similar to the 'two-beam plasma instability' for two- component collisionless plasmas. The research is to search for this effect by a) studying the current-voltage characteristics when a relative drift velocity exists between the two layers, and b) using bolometric detectors at low temperatures to detect the emitted radiation. The effect may have a long-term practical application in the design of generators of nearly monochromatic long-wavelength electromagnetic radiation.
