Open AccessInvestigation of height gradient in vertical plasma drift at equatorial ionosphere using multifrequency HF Doppler radar
Author(s) -
Prabhakaran Nayar S. R.,
Sreehari C. V.
Publication year - 2004
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004ja010641
Subject(s) - ionosphere , f region , depth sounding , radar , geology , geodesy , drift velocity , doppler effect , doppler radar , ionospheric sounding , altitude (triangle) , plasma , geophysics , physics , atmospheric sciences , geometry , quantum mechanics , telecommunications , oceanography , mathematics , astronomy , computer science
A multifrequency HF Doppler radar installed at the magnetic equatorial station Trivandrum provides an opportunity to study the height gradient in vertical plasma drift at the bottomside of equatorial F region during evening time. The multifrequency radar gives near‐simultaneous observation of vertical plasma drift at three close by F region heights above the sounding station. The height gradient of the vertical drift shows a negative value during the prereversal enhancement (PRE) period and turns to positive value after the prereversal enhancement. The average height gradient in vertical plasma drift remains negative around PRE and its magnitude decreases with altitude, below F peak. This could be a clear‐cut manifestation of the curl‐free nature of the low‐latitude electric field, and it could also indicate a partial signature of the postsunset velocity vortex at the equatorial F region. The magnitude of the mean height gradient around PRE exhibits a seasonal variation.