HR: 13:40h
AN: SM23D-01    [Abstracts]
TI: Solar-Wind Ion Motion in an Analytical Field-Line Model of the Magnetosheath
AU: * Chen, M W
EM: mchen@aero.org
AF: The Aerospace Corporation, P. O. Box 29597, M2-260, Los Angeles, CA 90266, United States
AU: Schulz, M
EM: mike.schulz@lmco.com
AF: Lockheed Martin Advanced Technology Center, 3251 Hanover Street, Dept ADCS, B/255, Palo Alto, CA 94303, United States
AU: Lemon, C L
EM: colby.lemon@aero.org
AF: The Aerospace Corporation, P. O. Box 29597, M2-260, Los Angeles, CA 90266, United States
AU: McNab, M C
EM: michael.c.mcnab@aero.org
AF: The Aerospace Corporation, P. O. Box 29597, M2-260, Los Angeles, CA 90266, United States
AB: We investigate the transport of representative solar-wind ions through the Earth's magnetosheath by tracing their trajectories in an analytical model of the magnetosheath, based on the draping of plasma streamlines and magnetic field lines around a conducting magnetopause that consists of a prolate ellipsoid, extending ~ 11 R_E upstream and ~ 65 R_E downstream from Earth, matched to a cylinder of radius ~ 28.4 R_E. The bow shock is well represented in our model by an axisymmetric paraboloid that intersects the Sun-Earth line about 26% farther upstream from the point dipole than the nose of the magnetopause does. For a uniform but arbitrarily directed interplanetary magnetic field (IMF), the magnetosheath's magnetic field can be obtained by superposition of results for special cases in which the IMF is respectively parallel to and perpendicular to the solar-wind velocity. For the case in which the IMF is parallel to the solar-wind velocity, the magnetosheath's magnetic field is derivable from Euler potentials that can be expressed analytically as a function of ellipsoidal or cylindrical coordinates that scale inversely with the sixth root of solar-wind pressure. When the IMF is perpendicular to the solar-wind velocity, we can calculate the magnetosheath flow velocity from Bernoulli's equation and compute the time delay for the magnetosheath plasma to have traveled to any point of interest from the bow shock. Points along a magnetosheath field line are points of equal time delay from an upstream field line. We compare the resulting field lines and streamlines with those obtained by Spreiter and Alksne [ Rev. Geophys., 7, 11-50, 1969] from their hydrodynamic calculation. As an application of our analytical model magnetosheath, we trace the full motion of representative solar-wind ions through it for different IMF configurations.
DE: 2728 Magnetosheath
DE: 2731 Magnetosphere: outer
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting