Study of coronal mass ejections and coronal holes associated mid-latitude geomagnetic storms observed during 1986-1996

摘要

A set of 103 mid-latitude large geomagnetic storms associated with increase in planetary index K_p≥7), which occurred during 1986-96 , has been analyzed. The yearly occurrence of these selected geomagnetic storms varies with the annual mean sunspot number (SSN) having some peculiarities. However, the number of observed storms is a maximum. During solar maximum period (1989-91). The occurrence of recurrent and non-recurrent types of mid-latitude large geomagnetic storms, during maximum and minimum phases of solar cycle 22 and their associated solar causes have also been analyzed.