  Neutral hydrogen has been shown to greatly impact the plasma flow in the
heliopshere and the location of the heliospheric boundaries. We present the
results of the Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics
(SHIELD) model, a new, self-consistent, kinetic-MHD model of the outer
heliosphere within the Space Weather Modeling Framework. The charge-exchange
mean free path is on order of the size of the heliosphere; therefore, the
neutral atoms cannot be described as a fluid. The SHIELD model couples the MHD
solution for a single plasma fluid to the kinetic solution from for neutral
hydrogen atoms streaming through the system. The kinetic code is based on the
Adaptive Mesh Particle Simulator (AMPS), a Monte Carlo method for solving the
Boltzmann equation. The SHIELD model accurately predicts the increased
filtration of interstellar neutrals into the heliosphere. In order to verify
the correct implementation within the model, we compare the results of the
SHIELD model to other, well-established kinetic-MHD models. The SHIELD model
matches the neutral hydrogen solution of these studies as well as the shift in
all heliospheric boundaries closer to the Sun in comparison the the multi-fluid
treatment of the neutral hydrogen atoms. Overall the SHIELD model shows
excellent agreement to these models and is a significant improvement to the
fluid treatment of interstellar hydrogen.

Space Physics;Solar and Stellar Astrophysics