Browsing by Author "La Hoz, C."

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    An imaging interferometry capability for the EISCAT Svalbard Radar
    (European Geosciences Union (EGU), 2005-01-31) Grydeland, Tom; Chau Chong Shing, Jorge Luis; La Hoz, C.; Brekke, A.
    Interferometric imaging (aperture synthesis imaging) is a technique used by radio astronomers to achieve angular resolution that far surpasses what is possible with a single large aperture. A similar technique has been used for radar imaging studies of equatorial ionospheric phenomena at the Jicamarca Radio Observatory. We present plans for adding an interferometric imaging capability to the EISCAT Svalbard Radar (ESR), a capability which will contribute significantly to several areas of active research, including naturally and artificially enhanced ion-acoustic echoes and their detailed relation in space and time to optical phenomena, polar mesospheric summer echoes (PMSE), and meteor studies. Interferometry using the two antennas of the ESR has demonstra ted the existence of extremely narrow, field-aligned scattering structures, but having only a single baseline is a severe limitation for such studies. Building additional IS-class antennas at the ESR is not a trivial task. However, the very high scattering levels in enhanced ion-acoustic echoes and PMSE means that a passive receiver antenna of more modest gain should still be capable of detecting these echoes. In this paper we pre sent simulations of what an imaging interferometer will be capable of observing for different antenna configurations and brightness distributions, under ideal conditions, using two different image inversion algorithms. We also discuss different antenna and receiver technologies.
    Palabras clave:IonosphereInterferometrySpace plasma physics
  • Thumbnail Image
    ItemRestricted
    Preliminary comparisons of VHF radar maps of F-region irregularities with scintillations in the equatorial region
    (Elsevier, 1977-09) Basu, Sunanda; Aarons, J.; McClure, J.P.; La Hoz, C.; Bushby, A.; Woodman Pollitt, Ronald Francisco
    Multiantenna 50 MHz radar backscatter maps of echo power from night-time F-region equatorial irregularities obtained at Jicamarca, Peru were compared with simultaneous VHF scintillation observations from Huancayo at 137 and 254 MHz during the period 20 November–12 December 1975. Saturation of VHF scintillations in excess of 20 dB was observed at both these frequencies during times when radar maps showed large intense plume structures rising into the topside ionosphere. On nights when only thin layers of bottomside irregularities were observed moderate to weak scintillations were recorded at VHF. Preliminary values of east-west horizontal irregularity drift velocities were obtained and compared with scintillation rate observations. Using the 1.5° and 4.5° longitudinal separation between the Jicamarca radar and ionospheric observation points of the two satellites from Huancayo, information was derived regarding large-scale east-west structure during the development phase of the irregularities.
    Palabras clave:Incoherent Scattering RadarIonosphereScintillation