Global dynamo simulation of ionospheric currents and their connection with the equatorial electrojet and counter electrojet : a case study - Inria - Institut national de recherche en sciences et technologies du numérique Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Année : 1983

Global dynamo simulation of ionospheric currents and their connection with the equatorial electrojet and counter electrojet : a case study

Résumé

The interrelationship of equatorial and planetary scale ionospheric horizontal currents on quiet days is studied by means of a global ionospheric wind dynamo simulation. This simulation aims at reproducing magnetic and radar data first for a normal quiet day, and then for the strong counterelectrojet event of January 21, 1977, which was previously studied in detail on the basis of coherent backscatter radar data for the Addis-Ababa location. For the reference quiet day (January 27, 1977), the pattern of low and middle latitude currents and electric fields can be roughly reproduced by a combination of the (1,-2) and (2,2) solar tides. Both the Sq current system, and the global electrostatic potential distribution as derived by Richmond et al. [1980] from incoherent scatter data are well simulated. Direct comparison of the computed electric field with the quiet-day averages available for each radar site also show an excellent agreement on the east-west component, but a poorer one on the northsouth component. The counterelectrojet simulation is performed by fitting the H component trace at the magnetic equator and the D trace at midlatitudes. The result appears to give a consistent solution to the problem of the electrical connection between the equatorial counterelectrojet and the planetary dynamo layer. Two horizontal current vortices of opposite directions are found to flow at low latitudes on each side of the noon sector, anticlockwise in the morning and clockwise in the afternoon. They both produce a poleward current flow at low latitudes at noon, a feature that is detected on the magnetic records. The counterelectrojet event is reproduced by a combination of the (2,2) and (2,#) solar tides, assuming that the contribution of the diurnal tide to the altitudeintegrated current flow cancels out. This result is in agreement with a previous simulation study of the counterelectrojet phenomenon.
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Dates et versions

hal-00977429 , version 1 (11-04-2014)

Identifiants

  • HAL Id : hal-00977429 , version 1

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Christian Hanuise, Christine Mazaudier, Paul Vila, Michel Blanc, Michel Crochet. Global dynamo simulation of ionospheric currents and their connection with the equatorial electrojet and counter electrojet : a case study. Journal of Geophysical Research, 1983, pp.253-270. ⟨hal-00977429⟩
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