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dc.contributor.authorOhtani, Shinici
dc.contributor.authorGjerløv, Jesper
dc.contributor.authorJohnsen, Magnar Gullikstad
dc.contributor.authorYamauchi, Masatoshi
dc.contributor.authorBrändström, Urban
dc.contributor.authorLewis, Andrew M.
dc.date.accessioned2019-12-06T13:51:17Z
dc.date.available2019-12-06T13:51:17Z
dc.date.issued2019-07-18
dc.description.abstractThe present study investigates the dependence of the local auroral electrojet (AEJ) intensity on solar illumination by statistically examining northward geomagnetic disturbances in the auroral zone in terms of the solar zenith angle χ. It is found that on the dayside, both westward and eastward electrojets (WEJ and EEJ) are more intense for smaller χ, suggesting that the solar extreme ultraviolet‐induced conductance is the dominant factor for the AEJ intensity. On the nightside, in contrast, the χ dependence of the AEJ intensity, if sorted solely by the magnetic local time, apparently depends on the station longitude and hemisphere. However, if additionally sorted by the dipole tilt angle ψ, a consistent pattern emerges. That is, although χ and ψ are correlated, the solar zenith angle and dipole tilt angle have physically different effects on the AEJ intensity. The nightside AEJ, especially the WEJ, tends to be more intense for smaller |ψ|. Moreover, whereas the WEJ is statistically more intense when the ionosphere is dark, the EEJ is more intense when it is sunlit. The preference of the WEJ for the dark ionosphere prevails widely in magnetic local time from premidnight to dawn, and therefore, it cannot be attributed to the previously proposed processes of the preferred monoenergetic or broadband auroral precipitation in the dark ionosphere. Instead, it may be explained, at least morphologically, in terms of the conductance enhancement due to the diffuse auroral precipitation, which is also prevalent from premidnight to dawn and is more intense in the dark hemisphere.en_US
dc.identifier.citationOhtani S, Gjerløv J, Johnsen MG, Yamauchi, Brändström U, Lewis. Solar illumination dependence of the auroral electrojet intensity: Interplay between the solar zenith angle and dipole tilt. Journal of Geophysical Research (JGR): Space Physics. 2019:1-18en_US
dc.identifier.cristinIDFRIDAID 1721992
dc.identifier.doihttps://doi.org/10.1029/2019JA026707
dc.identifier.issn2169-9380
dc.identifier.issn2169-9402
dc.identifier.urihttps://hdl.handle.net/10037/16821
dc.language.isoengen_US
dc.publisherAmerican Geophysical Unionen_US
dc.publisherWileyen_US
dc.relation.journalJournal of Geophysical Research (JGR): Space Physics
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430::Astrophysics, astronomy: 438en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430::Astrofysikk, astronomi: 438en_US
dc.titleSolar illumination dependence of the auroral electrojet intensity: Interplay between the solar zenith angle and dipole tilten_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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