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Auroral Physics

As described in Lectures 15 and 16, Earth's auroral regions are coupled to the solar wind, magnetosphere, and ionosphere and are therefore the site of a number of space weather phenomena. These include the electromagnetic radiation of the ``aurora borealis''and ``aurora australis'' (the ``northern'' and ``southern lights'', respectively), enhanced ionization and conductivity in the auroral ionosphere due to impact ionization processes, enhanced particle precipitation, and the rapidly varying magnetic fields associated with currents flowing in the auroral electrojet regions of the ionosphere. This Lecture contains a brief discussion of the physical processes involved in the production of the auroral lights, the different classes of auroral radiation associated with various precipitating particle populations, the existence of field-aligned currents and potential drops in the auroral regions, auroral substorms, and the auroral electrojets. The environment of the polar cap will also be discussed, including the characteristic size of the potential across the polar cap, the tex2html_wrap_inline315 motion of plasma across the polar cap, and the auroral electrojets.

Iver Cairns
Wed Oct 6 14:54:44 EST 1999