Study of cosmic ray intensity and geomagnetic storms with solar wind parameters during the period 1998–2005

Abstract

The aim of this paper is to study the effect of solar wind parameters (solar wind speed $V$, plasma flow pressure, and plasma density) on cosmic ray intensity and on geomagnetic storms for the period 1998–2005 (solar cycle 23). A Chree analysis by the superposed epoch method has been done for the study. From the present study we have found that the solar wind speed is a highly effective parameter in producing cosmic ray intensity decreases and geomagnetic storms. No time lag is found between cosmic ray intensity decreases, geomagnetic storms, and peak value of solar wind speed. Further, we have found that the plasma flow pressure is effectively correlated with geomagnetic storms but it is weakly correlated with cosmic ray intensity. The cosmic ray intensity and geomagnetic storms are found to be weakly correlated with plasma density. The decrease in cosmic ray intensity and geomagnetic storms takes place one day after the peak values of plasma flow pressure and plasma density. There is a time lag of one day between solar wind parameters (plasma flow pressure and plasma density) and cosmic ray intensity decrease, geomagnetic storms. Also, we have found a high correlation of cosmic ray intensity and geomagnetic storms with the product of interplanetary magnetic field $B$ and solar wind speed $V$ i.e. $B\cdot V$. This study may be useful in predicting the space-weather phenomena.