Incoherent scatter radar observations of the F-region ionosphere at Arecibo during January 1993

摘要: Abstract We report incoherent scatter radar observation of the F-region ion drift, plasma density, and electron temperatures during January 1993 World Day 10-day campaign. Although observed drift geomagnetically quiet period agrees with previous in horizontal direction to a large extent for similar geophysical conditions, vertical shows very downward component throughout entire day, which averages at about 20m s −1 near peak. Such average has not been reported before low latitudes. The motion comes mainly from along geomagnetic field line, is chiefly controlled by meridional wind day ambipolar diffusion night. E × B also contributes nighttime although it anti-correlation variation introduced line. During disturbed on 25 January, drifts showed departure period. perturbed eastward was highly correlated that magnetic field, may be indicative presence field-aligned current. Our daytime concentration temperature have contrasting correlations different altitude ranges F-region. They are positively below 180 km, anti-correlated between 220–400 well 440–620 again 660 km. While positive correlation km previously understood, less known systematically studied. Using energy balance equation, we show relationships depend composition lower altitudes; how heating via photoionization compares thermal conduction higher altitudes. motion, characteristics ionosphere all interrelated. present day-to-day variability as concentration.