Produção Nacional
Revisado por pares
Ionospheric irregularity zonal velocities over Cachoeira Paulista
2002; Elsevier BV; Volume: 64; Issue: 12-14 Linguagem: Inglês
10.1016/s1364-6826(02)00088-3
ISSN1879-1824
AutoresE. R. de Paula, I. J. Kantor, J. H. A. Sobral, H. Takahashi, D.C. Santana, D. Gobbi, A. F. Medeiros, L. A. T. Limiro, H. Kil, P. M. Kintner, M. J. Taylor,
Tópico(s)Solar and Space Plasma Dynamics
ResumoWe have studied the zonal drift velocity of nighttime ionospheric irregularities from Cachoeira Paulista (22.41°S,45°W, dip latitude −17.43°), a station under the Equatorial Anomaly, from December 1998 to February 1999 using L1 band GPS receivers and OI 630nm all-sky images. The average decimetric solar flux index for this period of increasing solar activity was about 145 and magnetically quiet days with ΣKp<24 were selected. The GPS technique used receivers spaced 55m in the magnetic east–west direction and probed small scale plasma structures (scale size about 400m) at altitudes near 350km. The zonal irregularity drift velocities measured by this technique were eastward with values of about 160m/s at 20 LT, about 140m/s around midnight, and decreased further in the post-midnight sector. The variability of these drifts decreased significantly after midnight. The zonal velocities of large scale plasma structure were obtained using OI 630nm all-sky images from a region located about 24.1°S and 45°W at a nominal height of 250km which corresponds to the bubble projection along the magnetic field lines to 350km over Cachoeira Paulista. These all-sky imager derived zonal drifts are also eastward, but have magnitudes smaller than the spaced GPS eastward drifts, particularly in the pre-midnight sector. We will discuss these two drift measurement techniques and the interpretation of our results.
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