East-West Plasma Bubble Irregularity Motion Determined from Spaced VHF Polarimeters: Velocity Shear in the Zonal F-Region Bulk Plasma Motion

摘要

VHF electronic polarimeters were used to monitor Faraday rotation angle and amplitude of geostationary satellite (GOES-3) beacon signals, simultaneously at two stations, Cachoeira Paulista and Sao Jose dos Campos, separated by 110km exactly in the magnetic East-West direction in Brazil. The analysis of the data for a few months in 1981-82 period shows TEC fluctuations correlated with range type spread F events in the local ionograms and amplitude scintillation in the satellite beacon signals, thereby identifying themselves as eastward propagating plasma bubbles, and structures within them, in the equatorial ionosphere. The nighttime variation pattern in these velocities is in excellent agreement with those of the eastward bulk plasma motion measured by Jicamarca radar, the irregularity patch movement obtained from closely spaced antennas over Natal, the eastward airglow patch velocities determined from all-sky 6300 A images over Ascension Island, and the thermospheric zonal winds measured by Fabry-Perot interferometer over Kwajalein Atoll. There exist, however, significant differences in the values of the eastward velocities for these different cases.