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Solar illumination control of ionospheric outflow above polar cap arcs

dc.contributor.authorMaes, L.
dc.contributor.authorMaggiolo, R.
dc.contributor.authorDe Keyser, J.
dc.contributor.authorDandouras, I.
dc.contributor.authorFear, R.C.
dc.contributor.authorFontaine, D.
dc.contributor.authorHaaland, S.
dc.date2015
dc.date.accessioned2016-03-24T12:08:13Z
dc.date.available2016-03-24T12:08:13Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/2780
dc.descriptionWe measure the flux density, composition, and energy of outflowing ions above the polar cap, accelerated by quasi-static electric fields parallel to the magnetic field and associated with polar cap arcs, using Cluster. Mapping the spacecraft position to its ionospheric foot point, we analyze the dependence of these parameters on the solar zenith angle (SZA). We find a clear transition at SZA between ∼94° and ∼107°, with the O+ flux higher above the sunlit ionosphere. This dependence on the illumination of the local ionosphere indicates that significant O+ upflow occurs locally above the polar ionosphere. The same is found for H+, but to a lesser extent. This effect can result in a seasonal variation of the total ion upflow from the polar ionosphere. Furthermore, we show that low-magnitude field-aligned potential drops are preferentially observed above the sunlit ionosphere, suggesting a feedback effect of ionospheric conductivity.
dc.languageeng
dc.titleSolar illumination control of ionospheric outflow above polar cap arcs
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeElectric fields
dc.subject.freeIonosphere
dc.subject.freeIons
dc.subject.freeIon outflow
dc.subject.freePolar cap
dc.subject.freePolar ionospheres
dc.subject.freePolar wind
dc.subject.freeSolar illumination
dc.subject.freeIonospheric measurement
dc.subject.freeatmospheric electricity
dc.subject.freeelectric field
dc.subject.freeflux measurement
dc.subject.freeionosphere
dc.subject.freemagnetic field
dc.subject.freespacecraft
dc.subject.freezenith angle
dc.source.titleGeophysical Research Letters
dc.source.volume42
dc.source.issue5
dc.source.page1304-1311
Orfeo.peerreviewedYes
dc.identifier.doi10.1002/2014GL062972
dc.identifier.scopus2-s2.0-84925799576


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