Low-latitude geomagnetic response to the interplanetary conditions during very intense magnetic storms

The variations in the horizontal and declination components of the geomagnetic field in response to the interplanetary shocks driven by fast halo coronal mass ejections, fast solar wind streams from the coronal hole regions and the dynamic pressure pulses associated with these events are studied. Close association between the field-aligned current density (j(parallel to)) and the fluctuations in the declination component (Delta D-ABG) at Alibag is found for intense storm conditions. Increase in the dawn-dusk interplanetary electric field (E-y) and Delta D-ABG are generally in phase. However, when the magnetospheric electric field is directed from dusk to dawn direction, it prominent scatter occurs between the two. It is suggested that low-latitude ground magnetic data may serve its it proxy for the interplanetary conditions in the solar wind. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.