Orientation of the local interstellar magnetic field inferred from Voyagers' positions

Abstract

Both Voyagers crossed already the termination shock (TS); Voyager 2 (V2) about 10 AU closer to the Sun than Voyager 1 (V1). The 10 AU difference in the distance reveals the scale of the shock asymmetry. Between several reasons of this asymmetry there is an asymmetric pressure from an interstellar magnetic field. Our goal is to determine what magnetic field strength and orientation produces a 10 AU asymmetry in the TS locations at V1 and V2, when only this factor would be taken into account. Here we show that such a shape of the TS, which would reflect the real positions of V1 and V2 when they crossed it is obtained for the magnetic field vector placed not far from the hydrogen deflection plane with inclination from interstellar flow ∼30°, and for the strength about 3.8 μG. Our predictions are compared with other results. Copyright 2008 by the American Geophysical Union.