Characteristics of heating in a mechanically vibrated superconducting coil

Abstract It is revealed that much heat is generated not only by the eddy current due to the relative displacement between conducting elements in a magnet, but also by the mechanical vibrating deformation of a superconducting coil [Suzuki, E., Cryog. Eng. , 1994, 29 , 495–503]. We measured the characteristics of heating in the mechanically vibrating superconducting coil in resonance using an oil servo actuator. As a result of these experiments, the following facts are made clear: (i) the heat generated in a vibrating superconducting coil is larger in the twisting configuration than in the bending one under the vibrating mode; (ii) the characteristics of the increment in heating in the vibrating coil under the energizing and the de-energizing state are almost the same. We cite as a factor in heating phenomena of the mechanical excitation the frictional heat between the fasteners and a superconducting coil. The size of the displacements in these frictional parts are supposed to be of the order of several micrometres. We intend to make further analyses of the heating phenomena.