Abstract

"Abstract: Space weather activity CMEs, and solar energetic particles from the Sun are carried out into space along with the solar wind. The wind speed sweeps toward the Earth at super sonic speed ranging from 300-1000 km/sec and distorts the Earth’s magnetic field. CMEs are the main cause of major geomagnetic storms. Geomagnetic storms are identified by using indices like Kp, Dst . According to the Richardson the most intense storms at both solar minimum and solar maximum are almost associated with CMEs. They occur when a sufficiently strong negative southward vertical component of the interplanetary magnetic field (IMF) Bz interacts with the Earth’s magnetosphere, when the dynamic pressure of solar wind is enchanced. The solar flare, CMEs and predominatly large magnitude of the IMF are the dominant phenomena during the high solar activity conditions. We have taken only 5 CME events out of 28 in year 2003 and all these events are Halo CMEs events. To study the effects of these CME events on geomagnetic field we have selected two stations, Alibag and Pondicherry with Geomagnetic Latitude and longitude (18.64N, 72.87E); (11.92N, 79.92E) respectively. The CME events were considered on 29 October 2003, 23 July 2003, 01 Nov.2003, and 28 October 2003. The data has been taken from Alibag and Pondicherry Geophysical Observatory. Three days have been taken during each event, one day before the event and one day after the event with the help of geomagnetic field Variations we can enlighten the effect of the CME on Earth. The severe event or epoch event of 29 october 2003 has IMF, Bz ≈-58nTwhich is very high value and produce large effect on the geomagnetic storm occur when solar wind long duration southward IMF impact Earth’s magnetosphere. During the geomagnetic storms southward IMF reconnect with Earth’s geomagnetic field at the dayside magnetopause, resulting a chain of events leading to the dramatic increase of ring current westward. The high speed CME affects more the geomagnetic field than the lesser one. According to the latitudinal variation the variation at Pondicherry is high as compare to the Alibag station with respect to their declination angle. As higher the declination angle lesser will be the variation. "

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