HR: 14:55h
AN: SH33B-06    [Abstracts]
TI: Direct Evidence for Magnetic Reconnection in the Solar Wind Near 1 AU
AU: * Gosling, J T
EM: jgosling@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Skoug, R M
EM: rskoug@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: McComas, D J
EM: DMcComas@swri.edu
AF: Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Smith, C W
EM: Chuck@briaxa.sr.unh.edu
AF: University of New Hampshire, Institute for Earth, Oceans, and Space, Durham, NH 03824 United States
AB: We have obtained direct evidence for local magnetic reconnection in the solar wind using solar wind plasma and magnetic field data obtained by the Advanced Composition Explorer (ACE). The prime evidence consists of accelerated ion flow observed within a magnetic field reversal region in the interior or at the rear edge of an interplanetary coronal mass ejection (ICME) on November 23, 1997. The observed plasma acceleration was consistent with the Walen relationship, which relates changes in flow velocity to density-weighted changes in the magnetic field vector. Pairs of proton beams having comparable densities and counterstreaming relative to one another along the magnetic field at a speed of ~2 Va, where Va was the local Alfven speed, were observed within portions of the accelerated flow event. We infer from the observations that reconnection occurred sunward of the spacecraft and that the accelerated flow occurred within a reconnection exhaust region bounded by Alfven waves and having a width of ~400,000 km. The counterstreaming ion beams resulted from solar wind plasma entering the exhaust region from opposite directions along the magnetic field. A similar reconnection-associated event was observed within an ICME on October 3, 2000; however, we have not yet identified additional events of this nature, possibly because predicted accelerations are relatively small for typical solar wind densities and magnetic field strengths.
DE: 7835 Magnetic reconnection
DE: 2109 Discontinuities
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting