@InProceedings{RodriguesPaulMill:2018:RaImEq,
               author = "Rodrigues, Fabiano S. and Paula, Eurico Rodrigues de and Milla, M. 
                         A.",
          affiliation = "{The University of Texas at Dallas} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Jicamarca Radio Observatory}",
                title = "Radar imaging equatorial spread F events",
                 year = "2018",
         organization = "Latin American Conference on Space Geophysics, 11. (COLAGE)",
             abstract = "Equatorial spread F (ESF) is the name given to signatures of 
                         ionospheric electron density irregularities observed by different 
                         types of ground- and space-based sensors. ESF irregularities have 
                         a wide spectrum of horizontal and vertical scale sizes, ranging 
                         from hundreds of km down to cm. Large-scale ESF structures are 
                         believed to be produced by the so-called ionospheric Generalized 
                         Rayleigh-Taylor (GRT) instability. This instability finds 
                         favorable conditions around sunset hours, near the magnetic 
                         equator when large vertical density gradients and enhanced upward 
                         plasma drifts are known to occur. Therefore, it explains the high 
                         occurrence of ESF irregularities in the post-sunset hours, and 
                         during periods when a pre-reversal enhancement of the upward ExB 
                         plasma drifts occur. Most of the main features of ESF, including 
                         its seasonal and longitudinal variability have been well studied 
                         and reported. Recent efforts have focused on advancing our 
                         understanding of the conditions leading to the short-term 
                         (day-to-day) variability in ESF. We also seek a better 
                         understanding, for instance, of unusual ESF events occurring 
                         outside typical ESF periods. Those include quiet-time events 
                         observed in the post-midnight sector, daytime, and during June 
                         solstice. Advances in numerical modeling of ESF have allowed us to 
                         better understand thermospheric and ionospheric conditions leading 
                         to ESF development and suppression. To keep up with numerical 
                         developments, new techniques and data sources need to be put in 
                         place to confirm theories and projections. New radar measurements 
                         and techniques can provide insights with that respect. In this 
                         presentation, we will talk about two-dimensional views of ESF 
                         events using observations made by relatively small radar systems. 
                         In the first part of the talk, we will present results of 
                         interferometric in-beam interferometric coherent scatter radar 
                         observations made in the Brazilian sector using a small, low-power 
                         radar system. In the second part of the talk, we will then present 
                         new coherent scatter observations of ESF events using measurements 
                         made by a 14-panel version of the AMISR system at the Jicamarca 
                         Radio Observatory in Peru. While the interferometric measurements 
                         provide high resolution observations of ESF scattering structures, 
                         they are limited in field-of-view. We show that the limitation in 
                         field-of-view can be overcome with AMISR-14 phased-array 
                         observations at the expense of zonal resolution. We will present 
                         and discuss results of both types of observations in light of 
                         current ESF theories and modeling.",
  conference-location = "Buenos Aires, Argentina",
      conference-year = "16-20 abr.",
             language = "en",
        urlaccessdate = "28 abr. 2024"
}