How Numerical Magnetic Dissipation at the Heliospheric Current Sheet Affects Model Predictions at Voyager 1 and Results from a Kinetic-MHD Model of the Heliosphere within SWMF

Several studies suggest that there is a need to move beyond ideal MHD in order to explain the Voyager 1 and 2 observations (Richardson et al. 2013; Michael et al. 2015). In the numerical simulations there is inherent and unavoidable numerical dissipation in the heliospheric current sheet that greatly exceeds the realistic dissipation rates. The magnetic dissipation inherent in modeling the heliospheric current sheet offers us a chance to explore non-ideal MHD effects in the heliosphere and heliosheath. In this work we investigate the role magnetic dissipation has on the overall structure of the heliosheath by comparing models describing the solar magnetic field both as a unipole and a dipole. We show that magnetic dissipation reduces the solar wind magnetic field strength over a significant fraction of the heliosheath. The region affected by the dissipation is increased when 11-year solar cycle variations in the solar wind are included and we discuss how this alters our prediction for Voyager 1 and 2 observations. We also present a new kinetic-MHD model of the outer heliosphere, which couples the Outer Heliosphere (OH) and Particle Tracker (PT) components within the Space Weather Modeling Framework (SWMF). The OH component uses the BATS-R-US MHD solver, a highly parallel, 3D, and block-adaptive code. The PT component is based on the Adaptive Mesh Particle Simulator (AMPS) model, a 3D, direct simulation Monte Carlo model that solves the Boltzmann equation for the motion and interaction of a multi-species gas within a plasma. The neutrals and plasma in the outer heliosphere are coupled through charge-exchange; the OH-PT model combines the MHD solution for the plasma with the kinetic solution for the neutrals to form a self-consistent model of the heliosphere. We present preliminary results of this model and discuss the implications on the structure of the heliosphere.