Heliospheric Current Sheet Crossings During the 1995-1996 Solar Minimum

Solar wind electron heat flux data allow us to determine the true polarities of the interplanetary magnetic fields. Past studies have generally focussed on transient structures, the interplanetary coronal mass ejections (ICMEs) that give rise to bidirectional electron heat fluxes. Many of these ICMEs occur in the heliospheric current sheet and form an integral part of the sector boundaries at 1 AU. The structure of the current sheet during solar minimum, when few ICMEs occur, has not yet been studied with the electron heat flux technique. We use plots of electron heat-flux pitch angles from the UC Berkeley 3D Plasma experiment on the Wind spacecraft during the last solar minimum of late 1995 and early 1996 to study the polarities of the magnetic fields close to the current sheet. The Wind spacecraft was often imbedded in the slow solar wind regions surrounding the current sheet at a time when few ICMEs were present. During several intervals of this period the magnetic field direction appeared to be poorly ordered in direction. We will characterize the basic magnetic structure near the current sheet at a time when the large-scale transient features are absent.