The invention provides a synchronous-generator stator, comprising a stator ring, a stator core, a circumferential gap between the stator ring and the stator core, and a plurality of decoupling units in the gap, wherein the decoupling unit has a first plate, which is matched to a contour of the stator core, and has a second plate, which is matched to the contour of the stator ring, wherein a mat, having a cavity and an inlet valve, is provided between the first and the second plate.