Equatorial electrojet as part of the global circuit: A case-study from the IEEY

A. T. Kobea, C. Amory-Mazaudier, J. M. Do, H. Lühr, E. Houngninou, J. Vassal, E. Blanc, J. J. Curto

Research output: Indexed journal article Articlepeer-review

23 Citations (Scopus)

Abstract

Geomagnetic storm-time variations often occur coherently at high latitude and the day-side dip equator where they affect the normal eastward Sq field. This paper presents an analysis of ground magnetic field and ionospheric electrodynamic data related to the geomagnetic storm which occured on 27 May 1993 during the International Equatorial Electrojet Year (IEEY) experiment. This storm-signature analysis on the auroral, mid-latitude and equatorial ground field and ionospheric electrodynamic data leads to the identification of a sensitive response of the equatorial electrojet (EEJ) to large-scale auroral return current: this response consists in a change of the eastward electric field during the pre-sunrise hours (0400-0600 UT) coherently to the high-, mid-, and equatorial-latitude H decrease and the disappearance of the EEJ irregularities between the time- interval 0800-0950 UT. Subsequent to the change in h'F during pre-sunrise hours, the observed foF2 increase revealed an enhancement of the equatorial ionization anomaly (EIA) caused by the high-latitude penetrating electric field. The strengthening of these irregularities attested by the Doppler frequency increase tracks the H component at the equator which undergoes a rapid increase around 0800 UT. The ΔH variations observed at the equator are the sum of the following components: SR, DP, DR, DCF and DT.

Original languageEnglish
Pages (from-to)698-710
Number of pages13
JournalAnnales Geophysicae
Volume16
Issue number6
DOIs
Publication statusPublished - Jun 1998
Externally publishedYes

Keywords

  • Auroral ionosphere
  • Electric fields and currents
  • Equatorial electrojet
  • Ionospheric disturbances
  • Magnetosphere-ionosphere interactions

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