@InProceedings{AbduKhBaPaMaSo:2013:GrWaSe,
               author = "Abdu, Mangalathayil Ali and Kherani, Esfhan Alam and Batista, Inez 
                         Staciarini and Paula, Eurico Rodrigues de and MacDougall, J. W. 
                         and Sobral, Jos{\'e} Humberto de Andrade",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {University of Western Ontario}",
                title = "Gravity wave seed perturbation and prereversal vertical drift in 
                         equatorial spread F/plasma bubble development under solar maximum 
                         and minimum conditions",
            booktitle = "Abstracts...",
                 year = "2013",
         organization = "Sientific Assembly, 12. (IAGA 2013).",
             keywords = "gravity wave, equatorial spread F.",
             abstract = "The post sunset development of the equatorial spread F/plasma 
                         bubble irregularities is known to be driven primarily by the 
                         evening (prereversal) enhancement in vertical drift/zonal electric 
                         field (PRE) and precursor seed perturbations in electron 
                         density/polarization electric field at the steep density gradient 
                         of the bottomside F layer. In this work we address the issue of 
                         the complementary influences from the PRE and seed perturbation in 
                         the ESF development process, during solar activity maximum and 
                         minimum conditions. The F layer heights at specific plasma 
                         frequencies as measured by Digisondes operated at equatorial and 
                         low latitude sites, including magnetic conjugate sites, in Brazil 
                         are analyzed to extract the characteristics of gravity wave 
                         oscillations in the F layer heights, of 0.5-1.5hrs periods, in the 
                         afternoon hours leading to possible post sunset ESF occurrence. 
                         The amplitude of these oscillations appears to undergo 
                         amplification just prior to the ESF onset in the ionograms of the 
                         solar maximum epoch. The importance of the seed perturbations 
                         relative to that of the PRE in the ESF instability initiation 
                         appears to vary significantly from the solar maximum to minimum 
                         epochs. While the solar cycle dependence of the PRE is fairly well 
                         known, that of the seed perturbation is poorly understood. The 
                         present analysis, complemented by simulation study of coupled 
                         Gravity wave-Interchange instability dynamics, is an attempt to 
                         understand better the importance of the instability seed 
                         perturbation relative to the PRE as the solar activity decreases 
                         from its maximum to minimum epochs.",
  conference-location = "Mexico",
      conference-year = "Aug. 26-31, 2013",
                label = "self-archiving-INPE-MCTI-GOV-BR",
             language = "en",
        urlaccessdate = "13 maio 2024"
}