The Effects of a Local Interstellar Magnetic Field onVoyager 1and2Observations

We show that that an interstellar magnetic field can produce a north/south asymmetry in solar wind termination shock. Using Voyager 1 and 2 measurements, we suggest that the angle $α$ between the interstellar wind velocity and magnetic field is 30∘ < α< 60∘. The distortion of the shock is such that termination shock particles could stream outward along the spiral interplanetary magnetic field connecting Voyager 1 to the shock when the spacecraft was within ~ 2~AU of the shock. The shock distortion is larger in the southern hemisphere, and Voyager 2 could be connected to the shock when it is within ~ 5~AU of the shock, but with particles from the shock streaming inward along the field. Tighter constraints on the interstellar magnetic field should be possible when Voyager 2 crosses the shock in the next several years.