The Janet/Busch Oscillator: A Multivibratory Dissipative Structure Relevant to Dynamo Theories of Geomagnetic Flux Reversals

A dynamo model of geomagnetism displaying multivibratory flux reversals is presented. This model employs a little-known but century-old motor/ generator system; it can be obtained from Bullard´s original series dynamo model by replacing his short-circuit with a virtual loaded capacitor, realized by a separately-excited motor. This resulting system furnishes a dissipative structure whose symmetry-breaking instability corresponds precisely to that of the Rayleigh/Van der Pol relaxation oscillator. Motor field strength determines the vibratory frequency. If the field varies, so does the frequency, yielding an infinite reversal period for a field becoming sufficiently weak.