Assessment of Joule heating for the observed distributions of high-latitude electric fields

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Abstract

[1] An assessment of Joule heating associated with electric field variability at high latitudes previously made by Codrescu et al. (1995) is refined with accounting for realistic probability density functions (PDFs) and root-mean-square (RMS) values of variable electric fields. It is shown that the observed PDFs constructed as functions of xEr/rms, Er being the amplitude and rms the root-mean-square amplitude of the residual field, which is left after subtracting the mean field Em from the data, can be fitted with a Castaing distribution. The parameter λ in this distribution that characterizes the degree of non-Gaussianity of data appears ∼0.7. Joule heating patterns are demonstrated for the electric fields observed in two passes of the low-altitude polar-orbiting Dynamic Explorer 2 (DE2) satellite over the high-latitude region in the Northern Hemisphere, one under positive IMF Bz in the presence of IMF By, and the other under negative IMF Bz. The relative contributions to Joule heating of the mean field, here considered as 1024 km running average of samples, and of the residual fields are estimated.

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