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The Retarding Potential Analyzer (RPA) and Ion Drift Meter
(IDM) onboard DE-2 satellite have provided the measurements
of ion density and ion drift velocity at F-region ionosphere
altitudes. Using the IDM data,we examine the average
characteristics of the zonal and vertical plasma flows in the
low-latitude region (< 50°MLAT) under the quiet geomagnetic
conditions (Kp < 3). The data reveal that the zonal ion
drifts are generally easrward at night, and westward at day
in both hemispheres. The night time ion drift speeds are much
larger than those of the day time. However, asymmetry in
vertical drift patterns exist between the two hemispheres.
Further,inspections on field-aligned components of the drift
patterns,we found that the hemispheric asymmetry in vertical
drift can be explained in terms of the interhemispheric
transport. Analyses of the RPA ion density measurements are
also carried out to study the latitudinal and local time
variations of the ion density distribution. Of particular
interesting observation is that the equatorial anomaly
density structures are most obviously seen in the evening
local time sector. The density peaks are located at ±(13
°- 21°) magnetic latitudes , consistent with the peaked
density locations as indicated in the IRI density profiles.
Finally, the advantage of using high resolution IDM on 35°
inclination ROCSAT-1 satellite to study the low-latitude
ionosphere dynamics will be discussed.
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