[P-EM13] Dynamics of the Inner Magnetospheric System

[PEM13-05] Observations of westward electric fields over low latitudes during long southward IMF Bz

*Sandeep Kumar¹、Kuldeep Pandey²、Yoshizumi Miyoshi¹、Dibyendu Chakrabarty³ (1.Institute for Space Earth Environmental Research, Nagoya University、2.ISAS, Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada、3.Physical Research Laboratory, Ahmedabad, India)

During disturbed times, interplanetary electric field (IEFy) enters the Earth’s ionosphere through open field lines in the high latitudes and promptly penetrates to the low latitude ionosphere. A sudden southward turning of interplanetary magnetic field (IMF) Bz is known to result in eastward/westward directed prompt penetration electric field on the dayside/ nightside ionosphere. However, on occasions, a westward electric field is observed over dayside low latitudes during long southward IMF Bz. A possible role of storm time substorms is examined to understand the unusual observation of westward ionospheric electric field under southward IMF Bz. The present work provides a detailed investigation on the prompt penetration electric fields during long southward Bz using multipoint observation from the ground and space.