Abstract:
In this article we have studied the association of Fds with geomagnetic storms and interplanetary shocks in the period of 1997-2013. We observed that the symmetric and asymmetric cosmic ray intensity decreases events are 47 and 74 respectively. Out of these events 29 and 62 events are found to be associated with geomagnetic storms respectively. Further we have observed that these symmetric and asymmetric cosmic ray intensity decreases are also associated with interplanetary shocks with the association rate 22 (46.81%), 60 (81.08%) respectively. The majority of interplanetary shocks following the onset of symmetric and asymmetric cosmic ray intensity decreases .We have 22 symmetric cosmic ray intensity decreases out which arrival time of 17(77.27%) interplanetary shocks have been found after the onset time of symmetric cosmic ray intensity decreases, The arrival time of 05(22.72%) interplanetary shocks have been found before the onset time of symmetric cosmic ray intensity decreases. We have 60 asymmetric cosmic ray intensity decreases out which arrival time of 37(61.66%) interplanetary shocks have been found after the onset time of asymmetric cosmic ray intensity decreases, The arrival time of 20(33.33%) interplanetary shocks have been found before the onset time of asymmetric cosmic ray intensity decreases and onset time of 03(5%) asymmetric cosmic ray decreases are common to arrival time of interplanetary shocks. Further we have found the positive correlation with correlation coefficient 0.09 and 0.60 between the magnitude of symmetric and asymmetric cosmic ray intensity decreases and geomagnetic storms respectively.
Keywords: Cosmic ray intensity, geomagnetic storms, interplanetary shocks.
Dr. Shiva Singh , Dr. Preetam Singh Gour