Equatorial spread- F and solar activity

Abstract

The effect of solar activity on equatorial spread- F has been studied using the published tables of f 0 F2 from six Afro-Asian stations. The strong negative correlation between equatorial spread- F and magnetic activity observed during sunspot maximum is no longer significant during low sunspot years. On the contrary, a positive correlation between occurrence of equatorial spread-F and magnetic activity is observed in winter of low sunspot years. Similar variations in h' F are also observed with respect to geomagnetic and solar activity. A severe reduction in the width of the belt of equatorial spread- F occurs in low sunspot years.