Entangled dynamos and Joule heating in the Earth's ionosphere
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Published:2020-09-24
Issue:5
Volume:38
Page:1019-1030
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ISSN:1432-0576
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Container-title:Annales Geophysicae
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language:en
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Short-container-title:Ann. Geophys.
Abstract
Abstract. The Earth's neutral atmosphere is the driver of the well-known solar quiet (Sq) and other magnetic variations observed for more than 100 years. Yet the understanding of how the neutral wind can
accomplish a dynamo effect has been incomplete. A new viable model is presented where a dynamo effect is obtained only in the case of winds perpendicular to the magnetic field B that do not
map along B. Winds where u×B is constant have no effect. We identify
Sq as being driven by wind differences at magnetically conjugate points and not by a neutral wind per se. The view of two different but entangled dynamos is favoured, with some conceptual analogy
to quantum mechanical states. Because of the large preponderance of the neutral gas mass over the
ionized component in the Earth's ionosphere, the dominant effect of the plasma adjusting to the winds is Joule heating. The amount of global Joule heating power from Sq is estimated, with
uncertainties, to be much lower than Joule heating from ionosphere–magnetosphere coupling at high latitudes in periods of strong geomagnetic activity. However, on average both contributions could
be relatively comparable. The global contribution of heating by ionizing solar radiation in the
same height range should be 2–3 orders of magnitude larger.
Publisher
Copernicus GmbH
Subject
Space and Planetary Science,Earth and Planetary Sciences (miscellaneous),Atmospheric Science,Geology,Astronomy and Astrophysics
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