Role of neutral winds in generating irregularities in equatorial F-region

Electron density and neutral wind velocity measurements were carried out by rocketborne probes from rocket ranges in India. The experiments were carried out at the time of the onset of spread-F at sunset hours. The results show that a neutral wind velocity in north-south direction greater than 100 m/sec is required to trigger spread-F. It is suggested that spread-F is generated by the interaction of neutral gas with ionospheric plasma.