Vertical winds and turbulence over Thumba

Rocket and radar investigation of background electrodynamics and bottom-type scattering layers at the onset of equatorial spread <i>F</i>

“…The first concerns the cause of the shear flow. The factors that can contribute have been analyzed individually in theoretical and experimental contexts by Anandarao et al (1978);Fejer (1981); Stenning (1981); Takeda and Maeda (1983); Farley et al (1986) and by , , and again by Eccles (1998) in more theoretical treatments. They include 1) zonal electric fields on flux tubes with significant Hall conductivity, as are responsible for driving the equatorial electrojet, 2) zonal winds on flux tubes with significant Pedersen conductivity, as drive the E and F region dynamos, 3) vertical winds, a largely unknown quantity, and 4) vertical boundary currents forced from above or below the flux tube in question.…”

Possible ionospheric preconditioning by shear flow leading to equatorial spread <i>F</i>

“…Equation (2) succinctly summarized the factors that influence the vertical electric field in the equatorial ionosphere. These factors have been discussed individually in theoretical and experimental contexts by a number of investigators including Anandarao et al (1978);Fejer (1981);Stenning (1981); Takeda and Maeda (1983);Farley et al (1986) and by , , and recently by Eccles (1998) and Eccles et al (1999) in more complete theoretical treatments. They include 1) zonal electric fields on flux tubes with significant Hall conductivity, as are responsible for driving the equatorial electrojet, 2) zonal winds on flux tubes with significant Pedersen conductivity, as drive the E and F region dynamos, 3) vertical winds, a largely unknown quantity, and 4) vertical boundary currents forced from above or below the flux tube in question.…”

Electric fields in the equatorial ionosphere derived from CHAMP satellite magnetic field measurements

“…These winds could have large effects on the EEJ, and possibly even cause counter-electrojet conditions (Raghavarao and Anandarao, 1980). Unfortunately very few studies exist on vertical wind effects at the equator, and those that do normally have data for only a few heights and rely on considerable extrapolation (Anandarao et al, 1978). Therefore, due to a lack of data and models, we are unable to include vertical wind effects in our present study.…”

“…Vertical winds can have a substantial effect on vertical polarization electric fields and consequently the zonal electric field in the E-region (Hysell et al, 2002). Anandarao et al (1978) report up to 20 m/s vertical winds in the equatorial region at altitudes of 95-100 km. These winds could have large effects on the EEJ, and possibly even cause counter-electrojet conditions (Raghavarao and Anandarao, 1980).…”