As I know main limitation of superconducting energy storage is Lorentz forces which are created by magnetic field and ultimately destroy a superconducting ring. But there exist so called plasmon waves or plasma waves which could spread in metals and plasma. If I no make mistake they don't create magnetic field.I wander if it's possible to create conditions when those plasmon waves will be dumpless and dissipationless (in superconductors?) and what will be limitation to energy density of this waves. Also if it's possible to use plasmons for energy storage?