Magneto-mechanical oscillations revisited

Here we study the temporal evolution of a magnetemechanical, inverted spherical pendulum. The oscillator is a rigid, stainless steel, hollow needle. The needle has one end fixed in a spherical-like articulation, while the other extremity has no mechanical contact. The oscillation is driven by a longitudinal, periodically magnetic field added to a constant value of a static field. A video camera takes simultaneously the optical images of the projections of the oscillating needle along two mutually normal directions. The pairs of temporal sequences are analyzed in the real space, phase space and Fourier space. Among all the external parameter that can be usually varied, like the strength of the static magnetic field, the amplitude and the frequency of the driving magnetic field, or the momentum of inertia of the oscillating body, of a crucial importance seems to be the magnetc-mechanical feed-back of the oscillating system.