HR: 16:30h
AN: SH12C-03    [PDF]
TI: Location of the termination shock: an attempt to reconcile recent Voyager observations with Ulysses/SWICS pickup ion data and other diagnostics
AU: * Izmodenov, V V
EM: izmod@ipmnet.ru
AF: Lomonosov Moscow State University, Department of Aeromechanics and Gas Dynamics, Faculty of Mechanics and Mathematics, Vorobevy Gory, Moscow, 119899 Russian Federation
AU: Gloeckler, G
EM: gg10@umail.umd.edu
AF: University of Maryland, Department of Physics and IPST, College Park, College Park, MD 20742 United States
AU: Malama, Y
EM: malama@ipmnet,.ru
AF: Institute for Problems in Mechanics Russian Academy of Sciences, Vorobevy Gory 101-1, Moscow, 119526 Russian Federation
AU: Kallenbach, R
EM: kallenbach@issi.unibe.ch
AF: International Space Science Institute, Hallerstrasse 6, Bern, 3012 Switzerland
AB: Our Solar System moves through a warm ($\sim$6,500 K), partly ionized local interstellar cloud (LIC) with a relative speed of $\sim$26 km/s. The solar wind interacts with the LIC to form a cavity around the Sun called the heliosphere. The solar wind meets the interstellar charged component at the heliopause, where solar wind pressure balances the pressure of the LIC. Before reaching the heliopause, the supersonic solar wind is decelerated at an extended shock wave, the heliospheric termination shock (TS). Here we apply our new multi-component time-dependent model of the interaction of the solar wind with the local interstellar medium to predict the location of the TS. We put constraints on the model parameters by using (1) IMP 8, ACE, Wind and Ulysses observations of the solar wind velocity and numbers density at one to several AU, (2) SWICS/ Ulysses pickup ion data, (3) Ulysses and Wind measurement of interstellar helium, and (4) recent results on ionization of helium and hydrogen in the LIC (Wolff et al., 1999). These four sets of observational data allow us to determine that the TS location should be between 93$-$100 AU in 2003. Our model predicts the heliopause location at $\sim$ 160 AU, which is in agreement with analyses of the heliospheric radio emission events of 1983$-$1984 and 1992$-$1994 at the plasma cutoff frequency 2.2$-$2.8 kHz detected by Voyagers 1 and 2. However, recent measurements of the enhanced fluxes of energetic particles observed by the LECP and CRS instruments on Voyager 1 suggest that Voyager 1 at $\sim$ 85 AU was close or beyond the TS during 2002/07-2003/02. In this paper we will try to reconcile recent Voyager observations with other diagnostics of the heliospheric interface and discuss different scenarios. Wolff, B., D. Koester and R. Lallement, Evidence for an ionization gradient in the local interstellar medium: EUVE observations of white dwarfs, Astron. Astrophys. 346, 969-978, 1999.
DE: 2124 Heliopause and solar wind termination
DE: 2144 Interstellar gas
DE: 2151 Neutral particles
DE: 2152 Pickup ions
DE: 2162 Solar cycle variations (7536)
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting