HF Doppler radar observations of equatorial plasma drifts and spread-F

The HF Doppler radar technique has been proven to be a valuable means for studying plasma motions in the F region of the equatorial ionosphere. The authors present, for magnetically quiet conditions, the Doppler observations dealing with (i) the postsunset vertical plasma drifts and their seasonal dependence, (ii) the prereversal enhancement in the vertical plasma drift and the occurrence of equatorial spread-F, and (iii) the vector plasma drift measurements for a sample equinoctial day.<
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