Relationship between the high-latitude electric and magnetic turbulence and the Birkeland field-aligned currents

摘要

We demonstrate the turbulent properties of the high-latitude electric and magnetic fluctuations, observed by the low-altitude polar-orbiting Dynamic Explorer 2 (DE2) satellite, by means of spectrum analysis and examination of the probability density function (PDF) of the fluctuations. To gain insight into the origin of the underlying turbulence, we calculate turbulent field patterns from DE2 observations under different IMF conditions and compare them with the associated patterns of the Birkeland field-aligned currents (FACs). A clear similarity of these two groups of distributions suggests a close, perhaps cause and effect relationship between the large-scale FACs and turbulent fields. This finding gives more evidence for the association of the turbulence under study and discrete auroral features, which are known to arise in the regions of strong background FACs.