Neutral interstellar gas atoms reducing the solar wind Mach number and fractionally neutralizing the solar wind

Many stars are known to drive stellar winds of the solar wind type. Thus wh en moving through the ambient interstellar medium these stars not simply io nize this medium but also interact as moving stellar wind systems. Only neu tral interstellar gas components can directly enter the inner stellar wind region and there undergo charge exchange reactions with the supersonic stel lar wind protons. Thereby the dynamical identities of plasma and gas compon ents are partially exchanged. The net effect is that energy is extracted fr om the wind plasma and transferred to newly created energetic neutral atoms (ENA) transporting the former wind energy over large distances into the di stant interstellar medium. As example for stellar wind systems in general, in the following we study quantitatively the effect of a loading of the ini tial solar wind plasma with transcharged neutral atoms connected with the i ncorporation of suprathermal pick-up ions and an associated reduction of th e effective solar wind sonic Mach number. In addition the removal of kineti c solar wind energy by neutralized solar wind protons leads to a nonclassic al reduction of the solar wind ram pressure and thereby a reduction of the location of the heliospheric termination shock. Our results indicate that a substantial percentage of the original solar wind energy is converted into a global flow of energetic neutral atoms and that the effective solar wind Mach numbers in the outer heliosphere are drastically reduced if presently quoted neutral H-atom densities in the outer heliosphere of 0.1 less than or equal to n(H infinity) less than or equal to 0.3 [cm(-3)] are in fact pr evailing.