author = "Pimenta, A. A. and Sahai, Y. and Bittencourt, Jos{\'e} Augusto 
                         and Abdu, M. A. and Takahashi, Hisao and Taylor, M. J.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Utah State University}",
                title = "Plasma blobs observed by ground-based optical and radio techniques 
                         in the Brazilian tropical sector",
              journal = "Geophysical Research Letters",
                 year = "2004",
               volume = "31",
             abstract = "Ground-based optical and radio observations were carried out in 
                         the tropical region in Brazil, during the period from October 1998 
                         to September 2000, and on several occasions we detected F-region 
                         plasma blob (localized discrete plasma density enhancement) 
                         events. These are the first observations of blobs in the tropical 
                         F-region using combined ground-based optical and radio techniques. 
                         Allsky images were used to map the spatial extension and temporal 
                         location of plasma blobs and ionosonde and photometer measurements 
                         were used to measure the plasma densities. Interesting cases of 
                         plasma blob events were observed on October 07, 1999 and March 04, 
                         2000 over Cachoeira Paulista (22.7S, 45.0W; magnetic latitude 
                         13.25S, declination 20W), showing discrete plasma density 
                         enhancements near regions of plasma density depletion structures 
                         in the OI 630.0 nm emission images. In these two cases, the 
                         electron densities were enhanced by a factor of, approximately, 2 
                         above the background level. In this paper we report the first 
                         ground-based observations of the plasma density enhancements, or 
                         blobs, and their association with equatorial spread-F plasma 
                         depletions, and suggest a possible mechanism for their 
                  doi = "10.1029/2004GL020233",
                  url = "http://dx.doi.org/10.1029/2004GL020233",
                 issn = "0094-8276",
             language = "en",
           targetfile = "Alexandre A Pimenta2.pdf",
        urlaccessdate = "18 jan. 2021"