HR: 14:00h
AN: SM43A-01 INVITED     [Abstracts]
TI: The Physics of the Foreshock: An Introduction
AU: * Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave , Los Angeles, CA 90095-1567, United States
AB: The foreshock is the region upstream from a collisionless shock in which energetic charged particles are flowing away from the shock and therefore streaming with respect to the solar wind. These particles can arise because they are "reflected" by the shock and because they are thermalized and scattered downstream of the shock but have sufficient thermal speed to move upstream. This latter process occurs above a critical Mach number so we refer to subcritical and supercritical shocks. Similarly ion reflection produces upstream beams only below theta BN angles of 39 deg. Thus we divide the shock into quasiparallel and quasiperpendicular regimes. Backstreaming electrons and ions create a plethora of waves from a panoply of instabilities and greatly modify the incoming flow. However, there is a second source of upstream waves: production at the shock itself. These whistler-mode waves generally affect only the region in and near the shock ramp and are only a factor at low Mach numbers, but these waves can exceed the solar wind velocity and propagate far upstream.
DE: 2154 Planetary bow shocks
DE: 2159 Plasma waves and turbulence
DE: 7829 Kinetic waves and instabilities
DE: 7851 Shock waves (4455)
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly