Method for operating a cooling device for cooling a superconductor and cooling device suitable therefor

A cooling device is disclosed for cooling a superconductor, wherein the cooling device includes a linear compressor for compressing a working medium and a cooling unit for providing a cooling power to a cryogenic coolant of the superconductor by expanding the working medium. The linear compressor includes two pistons of which at least one, preferably both synchronously relative to each other, are displaceable at a frequency and a stroke linear to the other piston, wherein a defined cooling power can be generated at a good efficiency so that the cooling device is suitable for use particularly in mobile installations, such as ships. To this end, according to at least one embodiment of the invention, the stroke of the at least one displaceable piston is controlled at a preferably prescribed target value.