Observations of magnetic reconnection in the turbulent high-speed solar wind

The high-speed solar wind that originates in coronal holes is permeated by evolved, Alfvenic-type fluctuations associated with MHD turbulence. We have used high temporal resolution (3 s) plasma and magnetic field measurements by the Wind spacecraft at 1 AU to identify and study Petschek-like reconnection exhausts in this turbulent flow for the first time. Despite the fact that the turbulent cascade produces numerous thin current sheets at 1 AU, such exhausts are relatively rare; we have identified only 34 reconnection exhausts in 1358 hr of highspeed solar wind data. With three exceptions, each exhaust was embedded within a relatively sharp, outward-propagating Alfvenic fluctuation. Local field shear angles across these reconnection exhausts ranged from 24 degrees to 160 degrees, with average and median values being similar to 90 degrees. The vast majority (88%) of these exhausts were narrower than 4 x 104 km and were convected past the spacecraft in < 66 s. Multispacecraft observations indicate that current sheets, and thus also reconnection X-lines, in the turbulent, high-speed wind are considerably more localized than in the low-speed wind or in interplanetary coronal mass ejections. The Wind observations demonstrate that reconnection is one way in which solar wind turbulence is dissipated and the high-speed wind heated far from the Sun, although it is not yet clear how effective reconnection is overall in this regard.