HR: 17:45h
AN: SH12C-08    [PDF]
TI: Interstellar Ne and Ar in the Heliosphere: Diagnostics of Interstellar Ionization and Outer Heliosphere Processes
AU: * Frisch, P C
EM: frisch@oddjob.uchicago.edu
AF: University of Chicago, Department of Astronomy and Astrophysics 5640 South Ellis Avenue, Chicago, IL 60637 United States
AU: Slavin, J D
EM: jslavin@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 34, Cambridge, MA 02138 United States
AB: Interstellar material dominates the mass density in the heliosheath, and the physical properties of the heliosheath regions are shaped by the interaction of the interstellar medium (ISM) with the solar wind. The characteristics of pickup ions, anomalous cosmic rays, and He observed inside of the solar system depend on the chemical composition and ionization of the cloud surrounding the solar system. Currently, radiative transfer models of the surrounding cloud, constrained by observations of ISM inside and outside of the heliosphere, provide the best determination of cloud properties. We present recent models of the surrounding cloud based on in situ and astronomical observations of the ISM. These models imply n(HI)~0.21 /cc at the solar location and subsolar interstellar abundances for many common elements. The models also yield direct predictions of filtration in the heliosheath regions, yielding F(H)~0.4, F(O)~0.6, F(N)~0.7, and F(Ar)~0.6. The robustness of these models is tested against observations and models of pickup Ne and anomalous cosmic ray Ar in the heliosheath regions, which in turn constrains the ionization of the surrounding interstellar cloud.
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2144 Interstellar gas
DE: 2151 Neutral particles
DE: 2152 Pickup ions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting