Numerical Modeling of the Heliosphere Using Interplanetary Scintillation Data as Boundary Conditions

Radio waves from distant, astronomical sources are scattered as they propagate through turbulent medium, such as the solar wind. The resulting random fluctuation in intensity observed is called interplanetary scintillation (IPS), which can be used in determining the solar wind properties, such as density and velocity. To numerically determine the plasma properties in the outer-heliosphere, such as the heliosheath where the Voyager spacecrafts are, we need the boundary conditions at some fixed distance from the Sun that are time-dependent and three-dimensional (3-D). Since IPS measurements cover a wide range of radial distances and latitudes, they fit the profile very well as such boundary conditions. The Center for Space Plasma and Aeronomic Research at the University of Alabama in Huntsville has developed a package of numerical codes called Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS) that are designed for solving ideal MHD equations with multiple discontinuities and simulating the complex flow of partially-ionized plasma in the outer heliosphere. In this study, we implement IPS data from the Solar-Terrestrial Environment Laboratory at Nagoya University in Japan as boundary conditions in MS-FLUKSS and compare the results with in situ measurements by spacecrafts for accuracy.