ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-23-1165-2005 Spatial and temporal variations of small-scale plasma turbulence parameters in the equatorial electrojet: HF and VHF radar observational results Manju G. 1 Viswanathan K. S. 1 Ravindran S. 1 Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum - 695 022, Kerala, India 03 06 2005 23 4 1165 1173 Copyright: © 2005 G. Manju et al. 2005 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/23/1165/2005/angeo-23-1165-2005.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/23/1165/2005/angeo-23-1165-2005.pdf

The spatial and temporal variations of various parameters associated with plasma wave turbulence in the equatorial electrojet (EEJ) at the magnetic equatorial location of Trivandrum (8.5&deg; N, 77&deg; E; dip 0.5&deg; N) are studied for the first time, using co-located HF (18MHz) and VHF (54.95MHz) coherent backscatter radar observations (daytime) in the altitude region of 95-110km, mostly on magnetically quiet days. The derived turbulence parameters are the mean electron density irregularity strength (&delta;n/n), anomalous electron collision frequency (&nu;<sub><i>e</i></sub>*) and the corrected east-west electron drift velocity (<i>V<sub>ey</sub></i>). The validity of the derived parameters is confirmed using radar data at two different frequencies and comparing with in-situ measurements. The behaviour of &delta;n/n in relation to the backscattered power during weak and strong EEJ conditions is also examined to understand the growth and evolution of turbulence in the electrojet.