Oscillatory instability of electromagnetically levitated solid bodies


Oscillatory instability of electromagnetically levitated solid bodies

Priede, J.; Gerbeth, G.

This paper presents a linear-stability analysis of small-amplitude oscillations of a solid body suspended in an alternating magnetic field. An original theory is developed for an arbitrary configuration of the magnetic field. Stability of a solid sphere in an axisymmetric linear magnetic field is calculated analytically. Oscillations of the sphere are found to develop as the frequency of the field exceeds certain critical threshold relative to the characteristic diffusion time of the magnetic field in the sphere. The critical frequency for the onset of oscillations in linear magnetic field coincides with the critical frequency for the spin-up instability in uniform magnetic field. The growth rate of oscillations attains a maximum at some frequency above the threshold and tends to zero at high frequencies.

  • Journal IEEE Transactions on Magnetics, USA, Vol. 36. No. 1, pp. 354-357, January 2000

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Publ.-Id: 1510