Solar cycle dependence of Pi2 pulsation activity in the equatorial region of India

Abstract

Solar Cycle dependence of Pi2 pulsation activity from the equatorial station at Choutuppal (Gm. Coord.: 7.5°N, 149°14′E), India, has been studied using pulsation data spanning nearly two solar cycles from 1970 to 1989. The Pi2 activity, primarily a nighttime phenomenon maximizing around local midnight shows an unambiguous inverse relationship with sunspot cycle. Equatorial Pi2 pulsation activity also shows a direct relationship with solar wind dynamic pressure variations. The results are discussed in relation to the associated phenomena like bursty flows in the plasma sheet and the possible influence of solar wind dynamic pressure variations.