HR: 11:10h
AN: SH32B-04    [Abstracts]
TI: Observations of Magnetic Reconnection in the Turbulent, High-Speed Solar Wind
AU: * Gosling, J T
EM: jack.gosling@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303, United States
AB: The high-speed (greater than 600 km/s) 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 hours of high-speed solar wind data. With 3 exceptions, each exhaust was embedded within a relatively sharp, outward-propagating Alfvenic fluctuation. Local field shear angles across these reconnection exhausts ranged from 24 to 160 degrees, with average and median values being close to 90 degrees. The vast majority (88%) of these exhausts had maximum local widths less than 4 x 10⁴ km and were convected past the spacecraft in less than 66 s, which is why they have not previously been identified in lower temporal resolution (1- min) data. Multi-spacecraft observations indicate that current sheets, and thus also reconnection X-lines, in the turbulent, high-speed wind tend to be 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.
DE: 2134 Interplanetary magnetic fields
DE: 2149 MHD waves and turbulence (2752, 6050, 7836)
DE: 2159 Plasma waves and turbulence
DE: 2164 Solar wind plasma
DE: 7835 Magnetic reconnection (2723, 7526)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting