@InProceedings{ArrudaSobAndAbdMas:2007:EvPrPe,
               author = "Arruda, D. and Sobral, Jos\é and Andrade, Humberto and Abdu, 
                         Mangalathayil Ali and Mascarenhas, M.",
          affiliation = "{} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Evidences of prompt penetration and disturbance dynamo electric 
                         field responses in the equatorial and low-latitude ionosphere 
                         during HILDCAA events",
            booktitle = "Proceedings...",
                 year = "2007",
         organization = "Latin-American Conference on Space Geophysics, 8. (COLAGE).",
             abstract = "This study focuses equatorial and low-latitude ionospheric 
                         responses to High Intensity Long Duration Auroral Electrojet 
                         Activity (HILDCAA) events. Such HILDCAA events, identified by 
                         Tsurutani and Gonzalez (1987), are characterized essentially by a) 
                         intense activities in the auroral zone during the absence of 
                         geomagnetic storm (main phase) and b) high frequency fluctuations 
                         in the north-south component of the interplanetary magnetic field. 
                         Equatorial and low-latitude ionospheric responses in the Brazilian 
                         sector (38o-45oW) are in the F-layer height and critical frequency 
                         modifications obtained from digisondes located at Cachoeira 
                         Paulista (low latitude region: 22.5oS, 45oW) and S{\"O}o Luis 
                         (equatorial region: 2oS, 44oW). Of all HILDCAA events analyzed, 3 
                         events that occurred on 11-14 May, 2001 (peak maximum solar), on 
                         3-7 July and on 20-25 August, 2003 (descending solar cycle) 
                         presented significant modifications as strong presences of prompt 
                         penetrating and disturbance dynamo electric fields that on 3-7 
                         July, 2003 were similar those observed during a typical 
                         geomagnetic storm, and low-latitude F-layer critical frequency 
                         increases attributed to equatorial anomaly expansion and 
                         thermospheric composition. This study is an extension of 
                         HILDCAA/Fast co-rotating beam event effects analyzed by Sobral et 
                         al. (2006) and it intends to contribute to improve theoretical 
                         simulations as well as the knowledge about near-Earth space 
                         weather.",
  conference-location = "Merida, Mexico",
      conference-year = "11-17 July",
             language = "en",
        urlaccessdate = "04 maio 2024"
}