A NEW MODEL OF INTERACTION BETWEEN THE SOLAR-WIND AND THE LOCAL INTERSTELLAR WIND

The interaction of subsonic plasma flow with a neutral particle cloud via charge exchange is considered. We derive a general expression for the velocity potential of the plasma how induced by charge exchange in teraction in the axisymmetric case. The particular case of the interac tion of uniform plasma flow with a spherically symmetric distribution of neutral particles is considered in detail. It is shown that charge exchange interaction is able to stagnate the plasma flow completely at a finite distance along the Stagnation line, and to redirect the plas ma how around the neutral cloud. We argue that this simple situation c ould represent the main features of the interaction of the interstella r wind with high-speed solar hydrogen flowing from the inner heliosphe re. Thus the heliopause could in part, if not as a whole, actually res ult from this particular form of charge exchange interaction. The degr ee of ionization of the local interstellar medium is shown to determin e the extent of the role of the charge exchange interaction. For a par tially ionized interstellar wind, charge exchange plays the main role in slowing down and stagnating the interstellar wind, while for a high ly ionized interstellar wind, its role is secondary to the direct gasd ynamic interaction of the two counter streaming plasmas.