Passive feedback stabilization of the levitated coil by means of superconducting loops

Passive feedback stabilization of levitated coils is often considered in connection with the design of internal ring devices (Multipole or Surmac). A novel method using short‐circuited superconducting coils as stabilizers has been proposed. We present here a numerical calculation of the stability of one levitated coil in the field of two other levitating coils. The stability is provided by a set of superconducting short‐circuited loops placed around the floating ring. Stable configuration does exist. We also found that for a given magnetic configuration there exists a minimum current in the levitated coil below which it is unstable.