Elliptical magnetic clouds and geomagnetic storms

Magnetic clouds are simple phenomena which modulate the interplanetary space and they are a subset of Interplanetary Coronal Mass Ejections. Due to the sustained orientation of their magnetic fields south- and northwards, they can influence the Earth's magnetosphere and may give rise to geomagnetic storms. Since such storms are dominant factors of space weather predictions, magnetic clouds are an important factor in this domain. We analyzed six observed magnetic clouds triggered a geomagnetic storm and simulate them in order to identify their characteristics, such as probable shapes, orientation of their axis, duration, etc. geomagnetic storms triggered by these clouds are investigated by their D,, indices. (c) 2007 Elsevier Ltd. All rights reserved.