Feasibility of a magnetic suspension for second generation Gravitational   Wave interferometers
  This paper deals with the use of a magnetic levitation system as a part of a multi-stage seismic attenuator for gravitational wave interferometric antennas. The proposed configuration uses permanent magnets in attraction to balance the suspended weight, plus a closed loop position control to obtain a stable levitation. The system is analyzed using a MATLAB simulation code to compute the forces exerted by extended magnets. The validity of this model has been tested by a comparison with the experimental data from a levitated suspension prototype. 
Monica Varvella, Enrico Calloni, Luciano Di Fiore, Leopoldo Milano,   Nicolas Arnaud