Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/39442
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dc.contributor.authorAmm, O.-
dc.contributor.authorAikio, A.-
dc.contributor.authorBosqued, J. M.-
dc.contributor.authorDunlop, M.-
dc.contributor.authorFazakerley, A.-
dc.contributor.authorJanhunen, P.-
dc.contributor.authorKauristie, K.-
dc.contributor.authorLester, M.-
dc.contributor.authorSillanpaa, I.-
dc.contributor.authorTaylor, M. G. G. T.-
dc.contributor.authorVontrat-Reberac, A.-
dc.contributor.authorMursula, K.-
dc.contributor.authorAndre, M.-
dc.date.accessioned2017-03-10T16:17:41Z-
dc.date.available2017-03-10T16:17:41Z-
dc.date.issued2003-08-31-
dc.identifier.citationAnnales Geophysicae , 2003, 21 (8), pp. 1737-1751 (15)en
dc.identifier.issn0992-7689-
dc.identifier.urihttp://www.ann-geophys.net/21/1737/2003/en
dc.identifier.urihttp://hdl.handle.net/2381/39442-
dc.description.abstractWe analyse a conjunction event of the Cluster II spacecraft with the MIRACLE ground-based instrument net-work in northern Fennoscandia on 6 February 2001, between 23:00 and 00:00 UT. Shortly after the spacecraft were located at perigee, the Cluster II satellites’ magnetic footpoints move northwards over Scandinavia and Svalbard, almost perfectly aligned with the central chain of the IMAGE magnetometer network, and cross a morning sector ionospheric shear zone during this passage. In this study we focus on the mesoscale structure of the ionosphere. Ionospheric conductances, true horizontal currents, and field-aligned currents (FAC) are calculated from the ground-based measurements of the IMAGE magnetometers and the STARE coherent scatter radar, using the 1-D method of characteristics. An excellent agreement between these results and the FAC observed by Cluster II is reached after averaging the Cluster measurements to mesoscales, as well as between the location of the convection reversal boundary (CRB), as observed by STARE and by the Cluster II EFW instrument. A sheet of downward FAC is observed in the vicinity of the CRB, which is mainly caused by the positive divergence of the electric field there. This FAC sheet is detached by 0.5°–2° of latitude from a more equatorward downward FAC sheet at the poleward flank of the westward electrojet. This latter FAC sheet, as well as the upward FAC at the equatorward flank of the jet, are mainly caused by meridional gradients in the ionospheric conductances, which reach up to 25 S in the electrojet region, but only ~ 5 S poleward of it, with a minimum at the CRB. Particle measurements show that the major part of the downward FAC is carried by upward flowing electrons, and only a small part by downward flowing ions. The open-closed field line boundary is found to be located 3°–4° poleward of the CRB, implying significant errors if the latter is used as a proxy of the former.en
dc.description.sponsorshipThe authors are grateful to the Principal Investigators, Henri Reme (CIS), Andr ` e Balogh (FGM), and G. ´ Gustaffson (EFW), for providing Cluster data. We like to thank R. Lepping (NASA/GSFC) and N. Ness (Bartol Research Institute) for data of the WIND and ACE satellites retrieved via CDAWeb. O.A. likes to thank the Academy of Finland for financial support. The MIRACLE network is operated within an international cooperation. Operations for the CUTLASS radar are funded by the Particle Physics and Astronomy Research Council (PPARC) and the Finnish Meteorological Institute. Research at CETP and CESR is supported by CNES (French Space Agency).en
dc.language.isoenen
dc.publisherEuropean Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany)en
dc.rights© Author(s) 2003. This work is distributed under the Creative Commons Attribution 3.0 License.en
dc.subjectScience & Technologyen
dc.subjectPhysical Sciencesen
dc.subjectAstronomy & Astrophysicsen
dc.subjectGeosciences, Multidisciplinaryen
dc.subjectMeteorology & Atmospheric Sciencesen
dc.subjectGeologyen
dc.subjectASTRONOMY & ASTROPHYSICSen
dc.subjectGEOSCIENCES, MULTIDISCIPLINARYen
dc.subjectMETEOROLOGY & ATMOSPHERIC SCIENCESen
dc.subjectionosphereen
dc.subjectelectric fields and currentsen
dc.subjectmagnetosphere physicsen
dc.subjectcurrent systemsen
dc.subjectplasma convectionen
dc.subjectALIGNED CURRENT SYSTEMSen
dc.subjectHARANG-DISCONTINUITYen
dc.subjectELECTRIC-FIELDen
dc.subjectLOW-ALTITUDEen
dc.subjectPOLAR-CAPen
dc.subjectCONVECTIONen
dc.subjectBOUNDARYen
dc.subjectACCELERATIONen
dc.subjectDMSPen
dc.subjectPRECIPITATIONen
dc.titleMesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observationsen
dc.typeJournal Articleen
dc.identifier.doi10.5194/angeo-21-1737-2003-
dc.identifier.eissn1432-0576-
dc.description.statusPeer-revieweden
dc.description.versionPublisher Versionen
dc.type.subtypeArticle;Journal-
pubs.organisational-group/Organisationen
pubs.organisational-group/Organisation/COLLEGE OF SCIENCE AND ENGINEERINGen
pubs.organisational-group/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomyen
dc.dateaccepted2003-02-25-
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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