The dependence of the LLBL thickness on IMF [formula omitted] and [formula omitted] components

Abstract

The thickness of the low latitude boundary layer (LLBL) is studied as a function of interplanetary magnetic field (IMF) using the data of THEMIS mission. The data from intersections of LLBL by Themis-A and -C satellites are analyzed. Solar wind parameters are provided by Themis-B satellite located before the bow shock. We use earlier developed method of LLBL thickness determination based on the analysis of the variation of plasma velocity in the layer perpendicular to the magnetopause. The database for the present analysis consists of 109 single satellite LLBL crossings where the values of LLBL thickness are obtained. The time shift of solar wind propagation from the spacecraft performing measurements outside the bow shock to the LLBL is taken into account. We analyze the dependence of LLBL thickness on IMF Bz and By using data of IMF measurements with 3s resolution and produce the 180s averaging of these data. Large scattering of the values of LLBL thickness and the weak dependence on IMF is demonstrated. Dawn–dusk asymmetry of LLBL thickness is not observed. The dependence of LLBL thickness on IMF clock angle is discussed.