Flows of partially ionized plasma are frequently characterized by the presence of both thermal and nonthermal populations of ions. This occurs, e. g., in the outer heliosphere, the part of interstellar space beyond the solar system whose properties are determined by the solar wind (SW) interaction with the local interstellar medium (LISM). Understanding the behavior of such flows requires us toinvestigate a variety of physical phenomena occurring throughout the solar system. The current proposal addresses the question the sky-spanning "ribbon" of unexpectedly intense emissions of ENAs detected by the Interstellar Boundary Explorer (IBEX) mission. By modeling the heliosphere using the resources of the Blue Waters facility at NCSA its becomes possible to analyze such puzzling astrophysical flows as those in the Guitar nebula, and compare modeling with remote observations. Numerical solution of these problems with the realistic boundary conditions provided by remote and in situ observations of the SW properties, requires the application of adaptive mesh refinement (AMR) technologies and petascale supercomputers. Codes developed during the NSF ITR program and various NASA projects will be used for the modeling and compared with observations by IBEX.
