J. Geophys. Res., in press (2000) 


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Self-consistent model of the solar wind interaction with three-component circumsolar interstellar cloud:  Mutual influence of thermal plasma, galactic cosmic rays, and H atoms

A. V. Myasnikov 1,D. B. Alexashov 1 , V. Izmodenov 2  and S. V. Chalov 1 

1 Institute for Problems in Mechanics, Russian Academy of Sciences, Prospect Vernadskogo 101, Moskow 117526, Russia
2 Moscow State University, Department of Mechanics and Mathematics, Aeromechanic division, Moscow 199899, Russia

Received May 11 1999 /Revised October 12 1999/ Accepted November 24 1999

Abstract
In this paper we continue our study of the galactic cosmic ray (GCR) influence on the structure of the heliospheric interface plasma flow  [Myasnikov et al., this issue]. The model presented here is more realistic and takes the mutual influence of plasma, neutral, and cosmic ray components into account self-consistently.
In the model, GCRs are described hydrodynamically under the assumption that their mass density is negligible; while neutrals are described kinetically. We explore the GCR influence on the heliospheric interface plasma structure by varying the diffusion coefficient, cosmic ray pressure, and adiabatic index. The problem is studied numerically, using the global iterations that couple the soft fitting technique for describing the plasma and GCR components and Monte Carlo simulations for H atoms. A strong GCR modulation is found in the heliospheric interface. At the same time, the  GCR influence on the plasma flow is negligible as compared with the influence of H atoms. The exception is the bow shock, a structure which can be strongly modified by the cosmic rays.
The Baranov--Malama model is therefore acceptable for interpretation of the physical processes in the heliosphere as long as the processes are not related to the bow shock structure. Although the simplest model of the cosmic ray transport is good enough to estimate GCR influence on the plasma and atom distributions in the heliospheric interface, more advanced models  should be used to interpret the observed GCR spectra.

Key words: heliospheric interface -- interstellar atoms -- galactic cosmic rays -- interstellar plasma -- solar wind