High-Latitude Electrical Currents and Joule Heating as Determined by SuperDARN, POLAR UVI

W. A. BRISTOW and D. LUMMERZHEIM

University of Alaska Fairbanks

One of the major channels for energy transfer from interplanetary space and the magnetosphere to the Earth’s upper atmosphere is through electrical currents and Joule heating in the high-latitude ionosphere. The global structure of the upper atmospheric winds, temperatures, and densities, depend on the large-scale pattern of this high-latitude energy deposition. Determining large-scale patterns of electrical currents and Joule heating requires knowledge of the convection electric field and the distribution of electrical conductivity. Currently, the best available means for these measurements is through the use of ground-based observations of convection, such as those determined by SuperDARN, in conjunction with global ultraviolet images such as those provided by the POLAR UVI. In this paper, examples are presented of the pattern of high-latitude electrical currents as determined by SuperDARN convection measurements in conjunction with the POLAR UVI estimates of the conductance. The period of observations includes a large substorm and illustrates the reconfiguration of the night-side electric field at substorm onset. This reconfiguration results in a diminishment of field-aligned currents after onset.

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