HR: 0800h
AN: SH21A-0290    [Abstracts]
TI: Slow Solar Wind Formation Beyond the Cusp of an Helmet Streamer
AU: * Rappazzo, A F
EM: rappazzo@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, MS 169-506, Pasadena, CA 91109,
AU: Velli, M
EM: mvelli@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, MS 169-506, Pasadena, CA 91109,
AU: Liewer, P
EM: paulett.liewer@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, MS 169-506, Pasadena, CA 91109,
AU: Lionello, R
EM: Roberto.Lionello@saic.com
AF: SAIC, 10260 Campus Point Dr, San Diego, ca 92121,
AU: Mikic, Z
EM: mikicz@saic.com
AF: SAIC, 10260 Campus Point Dr, San Diego, ca 92121,
AU: Einaudi, G
EM: einaudi@df.unipi.it
AF: Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, Pisa, 56127, Italy
AU: Dahlburg, R
EM: rdahlbur@lcp.nrl.navy.mil
AF: Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, dc 20375,
AB: The region beyond the cusp of an helmet streamer is characterized by the presence of a current sheet embedded in a plasma flow. In previous 3D and 2D simulations the velocity has been found, at a fixed radius, to grow from a slow value at the current sheet towards higher values towards the polar regions. The steady-state which was reached showed the bimodal characteristic of the solar wind, but the slow component did not show its characteristic variability. The velocity profile of the slow component is in fact not steady in time, and plasma density enhancements have been observed by the Large-Angle Spectrometric Coronagraph (LASCO) instrument on board the Solar and Heliospheric Observatory (SOHO). We present numerical simulations, performed with the SAIC MHD spherical code (MAS), of the region beyond the cusp of an helmet streamer from 1 R_\odot up to 20 R_\odot. With a sufficiently high resolution magnetic reconnection of the heliospheric current sheet is observed, which leads to the formation of density-enhanced magnetic islands that are accelerated radially outward. The reconnection process also gives rise to an acceleration profile that is not steady in time.
DE: 7524 Magnetic fields
DE: 7526 Magnetic reconnection (2723, 7835)
DE: 7839 Nonlinear phenomena (4400, 6944)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting