Characteristics of the equatorial F-region vertical plasma drift observed during post-sunset and pre-sunrise hours |
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Authors: | Tiju Joseph Mathew SR Prabhakaran Nayar Sudha Ravindran Tarun Pant |
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Institution: | 1. Department of Physics, University of Kerala, Trivandrum 695 581, India;2. Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum, India |
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Abstract: | Post-sunset and pre-sunrise vertical plasma drifts at the equatorial F-region have been investigated using the HF Doppler radar and ionosonde observations. Observed vertical plasma drift features during the sunrise are found to complement that observed during the evening. The post-sunset vertical plasma drift is characterized by an upward enhancement, a pre-reversal enhancement and a reversal in the drift direction. Similarly, the pre-sunrise plasma drift is characterized by a sudden downward excursion followed by an upward turning. The wavelet analysis of the plasma drift shows the presence of fluctuations in the period range 4–32 min and the short period fluctuations are attributed to the atmospheric gravity waves. |
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Keywords: | Equatorial ionosphere Short period fluctuations Pre-sunrise vertical plasma drift |
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