THE EFFECT OF MAGNETIC-FIELDS ON THE MACROSCOPIC INSTABILITY OF THE HELIOPAUSE .2. INCLUSION OF SOLAR-WIND MAGNETIC-FIELDS

The interstellar and solar plasma flows are kept separated from eachot her by an MHD discontinuity surface called the heliopause. Due to well known variations in the momentum flows of both plasmas the heliopause cannot be expected in a stationary, but in a time-variable non-equili brium state. We investigate the macroscopic stability of this surface with respect to linear perturbations. Whereas in paper I we have consi dered the effect of magnetic fields on the interstellar side, we now i nvestigate the effect of magnetic fields on the solar side of the heli opause. Interesting conclusions can be drawn with respect to the diffe rence in stability which concerns the ecliptic and the polar parts of the heliopause discontinuity. Furthermore, in the ecliptic parts it is of great relevance that the solar magnetic field changes its directio n with a rough period of 27 days and thus its inclination with respect to the shear flow vector of the adjacent heliopause plasmas. At some parts of the heliopause this periodically causes vanishing magnetic fi elds, and, in view of an interstellar held, also leads to constellatio ns of oppositely directed fields inside and outside of the heliopause with the consequence of magnetic reconnection occurring there.