@Article{BatistaAbduMedr:1990:MaAcEf,
               author = "Batista, Inez Staciarini and Abdu, Mangalathayil Ali and 
                         Medrano-Balboa, Rene Adalid",
                title = "Magnetic activity effects on range type spread-F and vertical 
                         plasma drifts at Fortaleza and Huancayo as studied through 
                         ionosonde measurements and theoretical modelling",
              journal = "EOS Transactions",
                 year = "1990",
               volume = "8",
               number = "5",
                pages = "357--364",
             keywords = "AERONOMIA, ionosfera, efeitos magn{\'e}ticos, magnetic effects, 
                         spreed F, ionosondes, equatorial regions, equinoxes, zonal flow, 
                         wind.",
             abstract = "Ionosonde measurements are used to study the effects of magnetic 
                         activity on spread F and on the postsunset enhancement (Vzmax) of 
                         the F region vertical plasma drift at two longitudinally separated 
                         stations, Fortaleza and Huancayo, situated along the magnetic 
                         equator, in the American sector. during a period of high solar 
                         activity. The analysis is made for three different levels of 
                         magnetic activity. It is seen that, during the winter, Vzmax and 
                         the range spread F occurrence (RSFO) in the premidnight hours 
                         systematically increase with Kp at both locations. During the 
                         summer and equinoxes the RSFO decreases with magnetic activity in 
                         the premidnight hours and increases in the postmidnight hours, the 
                         increase being generally more pronounced during very disturbed 
                         periods. On the other hand Vzmax deduced from ionosonde 
                         measurements shows almost no variation with magnetic activity 
                         during equinoxes and summer although during individual months of 
                         those periods both increases and decreases are seen. With the help 
                         of theoretical model calculations for the electrodynamical 
                         coupling between the equatorial E and F regions it is shown that a 
                         disturbance F region dynamo associated neutral wind could account 
                         for the variations of Vzmax with magnetic activity, that are 
                         consistently observed during winter months. On the other hand, 
                         competing influences of penetration electric fields, and/or those 
                         of disturbance meridional winds, seem to mask the expected gross 
                         effect of zonal winds in the summer and equinoctial months.",
                 issn = "2324-9250",
                label = "9294",
           targetfile = "8323.pdf",
        urlaccessdate = "08 maio 2024"
}