We examine here the possibility of current-driven plasma instabilities in superconductors in two temperature regimes. At low temperatures ($T\approx 0$) an instability can be generated in a layered system. Near the critical temperature ($T\approx T_c$) an instability can occur in a single superconductor for sufficiently large drifts which might be achievable in the new high-$T_c$ materials. These instabilities offer possibilities for new radiation-source device applications.

• Received 29 August 1988

DOI:https://doi.org/10.1103/PhysRevB.39.2852