Effect of magnetic cloud on cosmic ray intensity and geomagnetic field in association with coronal mass ejection and interplanetary shocks

The relationship between magnetic cloud and Coronal Mass Ejection is a part of research in this field. The view that all ICMEs would originate as flux ropes while only one-third of CMEs show clear magnetic cloud signatures. Magnetic clouds shows smoothed rotation of magnetic field. 106 Magnetic clouds were observed out of which 38 events are associated with CME and IP, 48 events are associated with CMEs and 36 with GMSs during the period of 1995–2007. Influence of these magnetic clouds alone, with CME, with CME and IP shocks and GMSs on the intensity of cosmic rays has been examined. The result of our study signifies that CME and IP shocks associated magnetic clouds remarkably produces large Forbush type decrease in cosmic ray intensity. It begins before onset time of magnetic cloud. Only CME associated shows lower variation in Cosmic Ray intensity than that of associated with CME and IP shocks while without any association produce least variation. Simultaneously higher geomagnetic activity observed. A plot is formed between average arrival hour time difference of geomagnetic storm and CME and number of days in respective year. We find that the arrival hour difference is maximum during maxima of solar cycle. A frequency histogram is plotted for finding probability of occurrence of geomagnetic storm for only magnetic cloud events or in association with CME, IP or both. We find that most of the geomagnetic storms are occurred for magnetic cloud events which are in association with both IP and CME.