Factors Influencing a Model Heliosphere

The value of accurate models of the global heliosphere continues to grow due to improvements in measurements of the remote regions of the heliosphere which have provided new and unexpected data. In order to explain this data models have continued to grow in complexity, adding previously ignored physics such as pick-up ion dynamics, Helium-Helium charge-exchange, and new estimates of Hydrogen density. In this presentation we quantify the influence of several such factors on the global features of the heliosphere. We also indicate characteristic values for parameters in the local interstellar medium that result in the best fit to observations.