E region electric fields at the dip equator and anomalous conductivity effects

• Published in: Advances in space research 2013-05, Vol.51 (10), p.1857-1869
• Main Authors: Denardini, C.M., Aveiro, H.C., Sobral, J.H.A., Bageston, J.V., Guizelli, L.M., Resende, L.C.A., Moro, J.
• Format: Article
• Language: English
• Subjects: Anomalous conductivity; E region; Electric field; Equatorial ionosphere
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/j.asr.2012.06.003

Zonal and vertical electric fields were estimated at E region heights in the Brazilian sector. Zonal electric fields are obtained from the vertical electric fields based on their relation through the Hall-to-Pedersen ionospheric conductivities ratio. The technique for obtaining the vertical electric field is based on its proportionality to the Doppler velocities of type 2 irregularities as detected by coherent radars. The 50MHz backscatter coherent (RESCO) radar was used to estimate the Doppler velocities of the type 2 irregularities embedded in the equatorial electrojet. A magnetic field-line integrated conductivity model was developed to provide the conductivities. It considers a multi-species ionosphere and a multi-species neutral atmosphere, and uses the IRI 2007, the MISIS 2000 and the IGRF 10 models as input parameters for ionosphere, neutral atmosphere and Earth’s magnetic field, respectively. The ion-neutral collision frequencies of all the species are combined through the momentum transfer collision frequency equation, and different percentages of electron-neutral collisions were artificially included for studying the implication of such increase in the zonal electric field, which resulted ranging from 0.13 to 0.49mV/m between the 8 and 18h (LT), under quiet magnetic conditions.