Postmidnight ionospheric troughs in summer at high latitudes

M. Voiculescu, T. Nygrén, A. T. Aikio, H. Vanhamäki, V. Pierrard

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In this article we identify possible mechanisms for the formation of postmidnight ionospheric troughs during summer, in sunlit plasma. Four events were identified in measurements of European Incoherent Scatter and ESR radars during CP3 experiments, when the ionosphere was scanned in a meridional plan. The spatial and temporal variation of plasma density, ion, and electron temperatures were analyzed for each of the four events. Super Dual Auroral Radar Network plasma velocity measurements were added, when these were available. For all high-latitude troughs the ion temperatures are high at density minima (within the trough), at places where the convection plasma velocity is eastward and high. There is no significant change in electron temperature inside the trough, regardless of its temporal evolution. We find that troughs in sunlit plasma form in two steps: the trough starts to form when energetic electron precipitation leads to faster recombination in the F region, and it deepens when entering a region with high eastward flow, producing frictional heating and further depleting the plasma. The high-latitude plasma convection plays an important role in formation and evolution of troughs in the postmidnight sector in sunlit plasma. During one event a second trough is identified at midlatitudes, with different characteristics, which is most likely produced by a rapid subauroral ion drift in the premidnight sector.

Original languageEnglish
Pages (from-to)12,171-12,185
JournalJournal of Geophysical Research: Space Physics
Volume121
Issue number12
DOIs
Publication statusPublished - Dec 1 2016

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troughs
polar regions
ionospherics
summer
trough
electrons
ions
Plasmas
plasma
temperature
radar
Electron temperature
Ions
temporal variation
spatial variation
ion temperature
electron
heat
ion
F region

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Voiculescu, M., Nygrén, T., Aikio, A. T., Vanhamäki, H., & Pierrard, V. (2016). Postmidnight ionospheric troughs in summer at high latitudes. Journal of Geophysical Research: Space Physics, 121(12), 12,171-12,185. https://doi.org/10.1002/2016JA023360

Postmidnight ionospheric troughs in summer at high latitudes. / Voiculescu, M.; Nygrén, T.; Aikio, A. T.; Vanhamäki, H.; Pierrard, V.

In: Journal of Geophysical Research: Space Physics, Vol. 121, No. 12, 01.12.2016, p. 12,171-12,185.

Research output: Contribution to journalArticle

Voiculescu, M, Nygrén, T, Aikio, AT, Vanhamäki, H & Pierrard, V 2016, 'Postmidnight ionospheric troughs in summer at high latitudes', Journal of Geophysical Research: Space Physics, vol. 121, no. 12, pp. 12,171-12,185. https://doi.org/10.1002/2016JA023360
Voiculescu M, Nygrén T, Aikio AT, Vanhamäki H, Pierrard V. Postmidnight ionospheric troughs in summer at high latitudes. Journal of Geophysical Research: Space Physics. 2016 Dec 1;121(12):12,171-12,185. https://doi.org/10.1002/2016JA023360
Voiculescu, M. ; Nygrén, T. ; Aikio, A. T. ; Vanhamäki, H. ; Pierrard, V. / Postmidnight ionospheric troughs in summer at high latitudes. In: Journal of Geophysical Research: Space Physics. 2016 ; Vol. 121, No. 12. pp. 12,171-12,185.
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