Connecting Properties of the Interstellar Medium to Observables Using Simulations of the Heliosphere

Our knowledge and understanding of the outer heliosphere has grown in leaps and bounds over the last decade, driven in tandem by advances in computational resources which have made 3D simulations with neutrals the standard, and by a range of new measurements of the farthest reaches of the heliosphere by the Voyager and IBEX spacecraft. Clearly we would like use as much of the available data as possible to parameterize the simulations, so that a consistent picture of the heliosphere may emerge. However, since the simulations obtain a solution to the boundary value problem, we only have freedom to manipulate the boundaries -- in the inner heliosphere and in the interstellar medium. Here we demonstrate how conditions in the interstellar medium can be used to satisfy various observed quantities in the heliosphere. We show that certain assumption about the interstellar medium correctly predict several observed features, while other assumptions may satisfy only one observation while leading to incorrect predictions for others. The goal is to identify those boundary conditions that result in the broadest agreement with observations.