Show simple item record

dc.contributor.authorRexer, Theresa
dc.contributor.authorGustavsson, Björn Johan
dc.contributor.authorLeyser, Thomas
dc.contributor.authorRietveld, Michael T
dc.contributor.authorYeoman, Tim
dc.contributor.authorGrydeland, Tom
dc.date.accessioned2019-01-16T07:38:44Z
dc.date.available2019-01-16T07:38:44Z
dc.date.issued2018-09-28
dc.description.abstractWe present first incoherent scatter radar observations of systematically recurring, high‐frequency (HF)‐enhanced ion line spectra at the topside F‐region ionosphere, during magnetic field aligned HF pumping in an O‐mode polarization. The European Incoherent Scatter UHF radar was directed in magnetic zenith on 9–11 March 2016 while stepping the pump frequency across the double resonance of the fourth harmonic of the electron gyrofrequency and the local upper hybrid frequency, in a 3‐min‐on, 3‐min‐off pump cycle. Topside and bottomside enhancements occur at the respective plasma resonance altitude and seem to be asymmetrically conditioned by the relative proximity of the pump frequency to the double resonance frequency. Further, the topside HF‐induced ion line enhancements predominantly appear while the pump frequency is just below the double resonance frequency and only simultaneous to strong bottomside enhancements. A powerful, HF radio wave in O‐mode, transmitted in the direction of magnetic zenith is reflected a few kilometers below the plasma resonance altitude, where the pump frequency is equal to the local plasma frequency, on the bottomside F‐region in the ionosphere. Transionospheric propagation of the pump wave outside the radio window can be facilitated by density striations in the plasma, and we consider, in detail, the possible mechanisms proposed for propagation outside the standard radio window.en_US
dc.descriptionAccepted manuscript version. Published version available at <a href=https://doi.org/10.1029/2018JA025822> https://doi.org/10.1029/2018JA025822</a>.en_US
dc.identifier.citationRexer, T., Gustavsson, B., Leyser, T., Rietveld, M.T., Yeoman, T. & Grydeland, T. (2018). First Observations of Recurring HF-Enhanced Topside Ion Line Spectra Near the Fourth Gyroharmonic. <i>Journal of Geophysical Research - Space Physics</i>, 123(10), 8649-8663. https://doi.org/10.1029/2018JA025822en_US
dc.identifier.cristinIDFRIDAID 1630626
dc.identifier.doi10.1029/2018JA025822
dc.identifier.issn2169-9380
dc.identifier.issn2169-9402
dc.identifier.urihttps://hdl.handle.net/10037/14453
dc.language.isoengen_US
dc.publisherAmerican Geophysical Union (AGU)en_US
dc.relation.ispartofRexer, T. (2021). Radio wave propagation through the ionosphere. (Doctoral thesis). <a href=https://hdl.handle.net/10037/22976>https://hdl.handle.net/10037/22976</a>.
dc.relation.journalJournal of Geophysical Research - Space Physics
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430en_US
dc.subjecttopside ion line spectraen_US
dc.subjectHF enhancementsen_US
dc.titleFirst Observations of Recurring HF-Enhanced Topside Ion Line Spectra Near the Fourth Gyroharmonicen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


File(s) in this item

Thumbnail

This item appears in the following collection(s)

Show simple item record