HR: 14:25h
AN: SH23A-04    [Abstracts]
TI: Diagnostics of Solar Wind Processes Using the Total Perpendicular Pressure
AU: * Jian, L
EM: jlan@igpp.ucla.edu
AF: University of California Los Angeles, Institute of Geophysics and Planetary Physics 405 Hilgard Avenue, Los Angeles, CA 90095-1567 United States
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: University of California Los Angeles, Institute of Geophysics and Planetary Physics 405 Hilgard Avenue, Los Angeles, CA 90095-1567 United States
AU: Gosling, J T
EM: jgosling@lanl.gov
AF: Los Alamos National Laboratory, SM-30, Bikini Atoll Rd., Los Alamos, NM 87545 United States
AB: The sum of thermal and magnetic pressure, the total pressure perpendicular to the magnetic field, is a very useful diagnostic of processes in the solar wind. Most notably total pressure has been used to study pressure-balanced structures in which the sum of the thermal and magnetic pressure is constant despite the changes in the constituents of the pressure, namely the densities and temperatures of the plasma species and the magnetic field. Such structures occur when magnetic field lines are relatively straight and exert no curvature force on the plasma, when pressure differences have equilibrated through propagating compressional waves, and the plasma is at rest relative to the surrounding solar wind flow. At times these conditions do not ensue. In stream-stream interactions a pressure gradient exists that accelerates the slower flow and decelerates the more rapid flow. Surrounding an expanding magnetic flux rope, which often lies at the heart of an ICME, there should also be a pressure gradient. The nature of this pressure gradient is very different than those at fast-slow stream interfaces. We show how this one parameter helps classify various solar wind structures and enables us to learn more about the geometry of ICMEs.
DE: 2102 Corotating streams
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 2139 Interplanetary shocks
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting