On flow reversal boundaries and transpolar voltage in average models of high-latitude convection

Lockwood, M. ORCID: https://orcid.org/0000-0002-7397-2172 (1991) On flow reversal boundaries and transpolar voltage in average models of high-latitude convection. Planetary and Space Science, 39 (3). pp. 397-409. ISSN 0032-0633 doi: 10.1016/0032-0633(91)90002-R

Abstract/Summary

The implications of polar cap expansions, contractions and movements for empirical models of high-latitude plasma convection are examined. Some of these models have been generated by directly averaging flow measurements from large numbers of satellite passes or radar scans; others have employed more complex means to combine data taken at different times into large-scale patterns of flow. In all cases, the models have implicitly adopted the assumption that the polar cap is in steady state: they have all characterized the ionospheric flow in terms of the prevailing conditions (e.g. the interplanetary magnetic field and/or some index of terrestrial magnetic activity) without allowance for their history. On long enough time scales, the polar cap is indeed in steady state but on time scales shorter than a few hours it is not and can oscillate in size and position. As a result, the method used to combine the data can influence the nature of the convection reversal boundary and the transpolar voltage in the derived model. This paper discusses a variety of effects due to time-dependence in relation to some ionospheric convection models which are widely applied. The effects are shown to be varied and to depend upon the procedure adopted to compile the model.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/38851
Item Type	Article
Refereed	Yes
Divisions	No Reading authors. Back catalogue items Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Elsevier
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