A digital data collection system for geomagnetic pulsation studies

Abstract

Geomagnetic pulsations are minute variations in the ultra-low frequency spectrum of the earth's magnetic field. In order to develop models to explain these phenomena we have first to record data of pulsation events. A flexible, microprocessor controlled data acquisition device suitable for operation at remote sites has been developed. This instrument demonstrates the feasibility of integrating a microprocessor controller with traditional geophysical sensors to create a conceptually simple, yet powerful, data recording device. Much information can be extracted from the data thus recorded. Geomagnetic pulsations are subdivided into several frequency bands; a digital computer routine has been developed which determines the signal power present in each band as a function of time. Pulsations signals tend to be elliptically polarized; another routine has been developed to calculate several polarization parameters, such as ellipticity and handedness, from these data.