S 68 Smolyak, B. M. The effect of ac magnetic fields on the lifting power of levitating superconductors / B. M. Smolyak, G. V. Ermakov, L. I. Chubraeva // Superconductor Science and Technology. - 2007. - Vol.20, №4. - С. 406-411 Рубрики: ФИЗИКА Кл.слова (ненормированные): LEVITATION FORCE -- SUPERCONDUCTING SUSPENSION -- LIFTING FORCE Аннотация: This study deals with the decrease in the levitation force under the action of an ac field up to the frequency at which oscillations of the superconducting suspension are limited by inertia. The lifting force was measured as a function of the ac field amplitude and the exposure time. It was shown that the force quickly decreased at the moment the ac field was applied and then continued diminishing, but at a lower rate. A qualitative model was proposed, taking into account two effects of the ac field on the magnetization of the levitating superconductor: a complete destruction of the critical state in some section of the superconductor (to a depth λac) and the initiation of a faster magnetic relaxation in the region where the induction gradient is preserved |