An axisymmetric magnetohydrodynamic model for the interaction of the solarwind with the local interstellar medium

We numerically analyze a magnetohydrodynamic, steady-state model for the in teraction of a spherically symmetric solar wind with a three-component loca l interstellar medium (LISM), which is composed of plasma, hydrogen atoms, and a magnetic field. The magnetic field is assumed to be parallel to the v elocity in the LISM. In this case, the model is axisymmetric. We study the effects of magnetic field on the plasma-flow geometry and on the distributi on of hydrogen-atom parameters. In particular, we show that the presence of hydrogen atoms does not affect the qualitative change in the shape of the bow shock, the heliopause, and the solar-wind shock with increasing strengt h of the interstellar magnetic field. The presence of a magnetic field in t he LISM can strongly affect the parameters of the energetic hydrogen atoms originated in the solar wind, although its effect on the "hydrogen wall" ob served with the GHRS instrument onboard the HST spacecraft (Linsky and Wood 1996) is marginal. (C) 2000 MAIK "Nauka/Interperiodica".