Dynamic cooperative behavior in a coupled-core fluxgate magnetometer

Recently, we have shown the emergence of oscillatory behaviour in unforced bistable systems having a dynamics of the general form: tau x = - partial derivative U(x, t)/partial derivative x, subject to carefully crafted coupling schemes. Here, we present experimental results obtained on a physical system implemented with N=3 coupled ferromagnetic cores; the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value, and, more importantly, the! oscillation characteristics are sensitive to weak external de magnetic fields. The oscillations afford then a novel detection scheme for Fluxgate magnetometer. In this paper we introduce an other idea; using the coupled core Fluxgate, in the detection of time-periodic fields of very low frequency. In This case measurements can be realized in a "power-saver" mode wherein the coupled setup can be, initially, subthreshold (i.e. non-oscillating) and be triggered into oscillation by the advent of the target (oscillatory) field. Preliminary experiments of this novel operation mode are here presented.