HR: 14:25h
AN: SH33B-04    [Abstracts]
TI: Propagation And Thermodynamics Of ICMEs In The Heliosphere: Observations And Simulations
AU: * Liu, Y
EM: liuxying@space.mit.edu
AF: Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AU: Richardson, J D
EM: jdr@space.mit.edu
AF: Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AU: Wang, C
EM: cw@space.mit.edu
AF: Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AU: Wang, C
EM: cw@space.mit.edu
AF: Center for Space Science and Applied Research, Chinese Academy of Sciences, P.O. Box 8701, Beijing, 100080 China
AU: Belcher, J W
EM: jwb@space.mit.edu
AF: Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AB: We conduct a statistical study of the propagation and thermodynamics of interplanetary coronal mass ejections (ICMEs) in the heliosphere. We base this study on a comprehensive survey of ICMEs from 0.3 to 30 AU observed at Helios 1 and 2, Ulysses, Wind and ACE, and Voyager 2 (Liu et al. 2004; Wang et al. 2004). We find that the radial width of ICMEs increases with distance out to 10-15 AU and then stays roughly constant; the radial width of near-Earth ICMEs has a solar cycle dependence, with a mean value of 0.34 AU. The expansion speed decreases very slowly, suggestive of a quasi-equilibrium expansion. The expansion is governed by a polytrope with $\gamma = 1.1-1.3$, indicating continuous heating in the ICME plasma. Coulomb collisions between alpha particles and protons are shown to play an important role in the heating process within ICMEs; other possible energy sources including heat flux electrons and dissipation of magnetic fluctuations are also investigated. A 1D MHD model including pickup ions is used to simulate the dynamical expansion of ICMEs with diverse artificial inputs at 1 AU; preliminary results predict that ICMEs over-expand, with maximum width near 5 AU. We will compare the model results and observations.
UR: http://web.mit.edu/liuxying/www/
DE: 7843 Numerical simulation studies
DE: 7859 Transport processes
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting