The Structure of the Outer Heliosphere: Numerical Simulations vs. Spacecraft Observations

The outer heliosphere is the part of the solar wind (SW) which is determined by its interaction with the local interstellar medium (LISM). Since the LISM is partially ionized, charge exchange between atoms and ions plays a major role in the SW-LISM interaction. The topology of this interaction will be described as a function of the SW and LISM properties. The coupling of the interstellar and interplanetary magnetic fields (IMF and ISMF) at the heliospheric interface will be described. The importance of pick-up ions will be emphasized.

Several examples of numerical solution of the SW-LISM interaction problem will be given in the attempt to match them the observations performed by the Voyager 1 (V1) and Voyager 2 (V2) spacecraft. The combined effect of charge exchange and ISMF pressure on the heliospheric asymmetries will be analyzed. Observational constraints on the ISMF orientation will be addressed. I will also show the interaction of the heliospheric discontinuities with the SW perturbations. Special attention will be given to the heliospheric response to Sun’s rotation and 11-year period of solar activity.

Finally, I will describe a suite of numerical codes developed by our research group in CSPAR/Physics Department. This suite is capable of performing rather sophisticated, very high-resolution calculations of a variety of problems in space physics.

Nikolai V. Pogorelov

UAHuntsville