Title: Investigation of Solar Influence on Thermospheric Density Variation
Abstract: Due to undulations in the heliospheric current sheet, the Earth’s orbit is divided into sectors where the sun’s interplanetary magnetic field (IMF) at the Earth is primarily directed towards or away from the sun. During the year 2003, the IMF direction at the Earth changes with a nearly consistent periodicity of 12-15 days, leading to well defined IMF sectors. During this same period, thermospheric neutral particle densities and electron content are higher during times when the IMF is directed towards the sun, and lower when the IMF is directed away from the sun. Possible links between the IMF polarity and thermospheric densities were investigated, with a focus on the spatial distribution of thermospheric density variations between IMF sectors, as well as the temporal changes of solar wind and IMF parameters and geomagnetic activity indices during the Earth’s transition between IMF sectors.