HR: 1340h
AN: SH33A-1187 INVITED     [Abstracts]
TI: On the assumptions commonly made for the evaluation of the compression, speed, normal orientation of a collisionless magnetohydrodynamic (MHD) shock, and their limitations
AU: * Berdichevsky, D B
EM: xrdbb@lepvax.gsfc.nasa.gov
AF: L3 GSI, 1801McCormickDrive, Suite 170, Largo, MD 20774 United States
AU: * Berdichevsky, D B
EM: xrdbb@lepvax.gsfc.nasa.gov
AF: NASA/Goddard Space Flight Center, Mail Stop 690, Greenbelt, MD 20771 United States
AB: The magnetohydrodynamic Rankine-Hugoniot conditions for a shock are reviewed. The requirements for the computation of the fast forward interplanetary shock parameters and their uncertainties are presented. The underlying assumptions used in the evaluation of the shock parameters are discussed. The applied technique is a combination of the "pre-averaged" magnetic-coplanarity, velocity-coplanarity, and the Abraham-Schrauner-mixed methods (1). It is shown that within acceptable limits this technique generally gave good results, with some exceptions. Arguments are presented that a nearby-located MHD discontinuity would cause the failure of the applied technique. Examples of that situation are presented. In these cases the shock normal is identified with the help of data from multiple spacecraft located within hundreds of earth radii distance from each other. Here the assumption is that within hundreds of earth radii distances the shock curvature is negligible. (This assumption appears to be valid for locally-driven transient shocks.) (1) Berdichevsky et al., J. Geophys. Res., 105, 27,289-27,314, 2000; Errata in J. Geophys. Res., 106, 25,133, 2001
DE: 7811 Discontinuities
DE: 2116 Energetic particles, planetary
DE: 2134 Interplanetary magnetic fields
DE: 2139 Interplanetary shocks
DE: 2149 MHD waves and turbulence
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting