Ulysses observations of sector boundaries at aphelion

We study a sample of sector boundaries observed by Ulysses near its early 1 998 aphelion at 5.4 AU. We relate these sector boundaries to solar wind str ucture seen by Wind at 1 AU, guided by a hydrodynamic simulation. For each Ulysses sector boundary we are able to identify a corresponding 1 AU sector boundary, except when strong transients are present. Sector boundaries app ear embedded in complex plasma structures that generally are in a state of pressure balance. Minimum variance analysis confirms the tangential discont inuity nature of the heliospheric current sheet (HCS) and indicates that th e current sheet tends to be inclined more steeply than at 1 AU (HCS normal closer to the equatorial plane and nearly radially outward). We discuss evi dence for the nonplanarity of the current sheet. Magnetic field depressions are characteristic features of the sector boundaries. We attribute them to particles that are magnetically confined inside the current sheet and that carry the diamagnetic current responsible far the large magnetic field rot ation.