Five‐station observations of Pc 1 micropulsation propagation

Abstract

An experimental study has been conducted on the characteristics of the propagation of mid‐latitude Pc 1 micropulsations using a five‐station receiving network stretching from New York to Florida and from Maryland to Illinois. All data were telemetered in real time over telephone data lines for centralized recording and analysis. Cross‐correlation techniques were used to determine group velocity and direction of arrival using three different computational methods. Amplitude, spectral, and polarization characteristics are presented for the data analyzed. It was found that the propagation direction tended to coincide approximately with that of the geomagnetic meridian in the vicinity of the network of sites and that the propagation was characterized better by curved wave fronts than by plane wave fronts. No examples of east–west propagation were observed, but this is to some extent a consequence of the mid‐latitude location of the observation sites. Propagation group velocities ranging from 444 to 1523 km/s were observed. Variation in group velocity for a given event over a period of an hour was typically less than 10%. Attenuation rates ranging from 0 to 13 dB/1000 km, with an average of 6.5 dB/1000 km, were observed.