An alternating current (AC) generator and method of operating the generator are provided. The generator includes a pair of two opposing cylinders. Each cylinder includes a high-temperature superconductor material at a temperature. The superconductor material is in a superconducting state in the presence of an external magnetic field below a critical field strength, wherein the critical field strength is a function of the temperature of the superconductor material. A sum of a non-zero time-invariant magnetic field strength and a time-varying magnetic field strength cycles between at least a first field strength below the critical field strength for the superconductor material at the temperature and at least a second field strength above the critical field strength for the superconductor material at the temperature, such that the superconductor material cycles between a superconducting state and a non-superconducting state. The generator further includes a piston configured to move within the two cylinders. The piston includes a permanent magnet having a magnetic field that interacts with the superconductor material of each of the two opposing cylinders. A time-varying force is applied to the magnet by an interaction of the magnet's magnetic field with the superconductor material. The generator further includes a pickup coil positioned so that movement of the magnet induces an electrical current in the pickup coil.