@Article{BatistaAbSoBeMaCaBa:2006:UnEaMo,
               author = "Batista, Inez Staciarini and Abdu, Mangalathayil Ali and Souza, 
                         Jonas Rodrigues and Bertoni, Fernando Celso Perin and Matsuoka, M. 
                         T. and Camargo, P. O. and Bailey, G. J.",
          affiliation = "Instituto Nacional de Pesquisas Espaciais, Divis{\~a}o de 
                         Aeronomia (INPE.DAE) and Instituto Nacional de Pesquisas 
                         Espaciais, Divis{\~a}o de Aeronomia (INPE.DAE) and Instituto 
                         Nacional de Pesquisas Espaciais, Divis{\~a}o de Aeronomia 
                         (INPE.DAE) and Instituto Nacional de Pesquisas Espaciais, 
                         Divis{\~a}o de Aeronomia (INPE.DAE) and {Universidade Estadual 
                         Paulista} and {Universidade Estadual Paulista} and {University of 
                         Sheffield}",
                title = "Unusual early morning development of the equatorial anomaly in the 
                         Brazilian sector during the Halloween magnetic storm",
              journal = "Journal of Geophysical Research",
                 year = "2006",
               volume = "111",
               number = "A5",
                pages = "A05307 (10pp)",
                month = "May",
             keywords = "low latitudes, electric-field, ionosphere, region, model, 
                         satellite, radar, drif.",
             abstract = "The solar events that occurred at the end of October 2003 gave 
                         rise to very strong geomagnetic disturbances that peaked twice 
                         with Dst values reaching -345 nT around 0000 UT on 30 October and 
                         -400 nT around 2300 UT, on the same day. Disturbances in several 
                         ionospheric parameters were observed over Brazil. This work will 
                         focus on the ionospheric response to the initial westward prompt 
                         penetration electric field and on the strong intensification of 
                         the equatorial ionization anomaly that occurred because of the 
                         electric field polarity reversal that followed in the early 
                         morning hours of 29 October. The F layer peak height over the 
                         equator first decreased under the strong prompt penetration 
                         westward electric field, which was followed by significant height 
                         increase under eastward electric field. We have used Sheffield 
                         University Plasmasphere Ionosphere Model (SUPIM) with an 
                         intensified westward disturbed electric field in the presunrise 
                         hours, presumably due to prompt penetration from the 
                         magnetosphere, in order to study the effect of such a field in the 
                         ionosphere. The simulation results showed that prompt penetration 
                         of magnetospheric electric fields of westward polarity to the 
                         nightside equatorial region seems to be the most probable cause of 
                         the initial F layer height decreases. The intensification of the 
                         equatorial ionization anomaly and the unusual enhancement on F 
                         layer peak density, which was not modeled by the SUPIM, are 
                         explained as caused by the strong eastward electric field that 
                         followed the initial phase in combination with a highly variable 
                         disturbed meridional/transequatorial wind system as inferred from 
                         the F2 layer peak height variations. The highly dynamic wind 
                         pattern, with a short-term response (2-4 hours), is compatible 
                         with the predictions of some previous theoretical model 
                         calculations reported in the literature.",
                  doi = "10.1029/2005JA011428",
                  url = "http://dx.doi.org/10.1029/2005JA011428",
                 issn = "0148-0227 and 2156-2202",
             language = "en",
           targetfile = "jgra18183.pdf",
        urlaccessdate = "29 jun. 2024"
}