Draping of the Interstellar Magnetic Field Over the Heliosphere - A Passive Field Model

We consider the idealized situation of a passive magnetic field, frozen into an otherwise uniform plasma flow, as the flow encounters a rigid heliospheric obstacle. We model the heliopause as a Rankine half-body and obtain an analytical solution for the steady-state field and flow structure that results. This idealized model provides a qualitative picture of the draped field structure which complements recent reports from detailed numerical simulations and can yield a more intuitive understanding of the conditions in the outer heliosheath. We apply this formalism to issues raised by observations of the IBEX ribbon position and by the magnetic field measurements at Voyager 1. Further implications will also be discussed.