Analysis of a PC-3 Micropulsation in the Geomagnetic Field

摘要

The Naval Postgraduate School has an ongoing effort to study geomagnetic noise and micropulsations in the ULF frequency range (.05 < f < 10 Hz). Data is collected by three orthogonally mounted coils at a remote land site and telemetered to the laboratory for computer analysis. To isolate data containing a micropulsation event, time series plots of the magnetic field were generated. The development of a double running average routine made possible the isolation of micropulsations in large data sets. A type PC-3 micropulsation was found and the coherence, ellipticity and polarization properties were determined as follows: Coherence = 0.99, Degree of Polarization = 0.99 and the micropulsation was elliptically polarized. Power spectral density (PSD) plots summarizing data segments about two hours long occasionally contained structures found to be artificial and not representative of natural phenomena in the geomagnetic field. Methods to avoid this anomalous behavior in PSD plots are suggested. (Author)