A Time-dependent Model of the Ambient Solar Wind and Turbulence Driven by Empirical Boundary Conditions

Abstract:

The solar wind is a turbulent medium through which energy and magnetic field are convected outward from the Sun. As the solar wind expands toward the Earth's orbit, stream interactions develop at the interface between fast and slow streams in the ambient solar wind that often contribute to space weather events. Large-scale disturbances such as coronal mass ejections interact with the background solar wind as they propagate through interplanetary space. Thus, modeling the ambient solar wind is an important part of space weather studies. The current operational models such as the Wang-Sheeley-Arge-Enlil (WSA-Enlil) model neglect the effects of turbulence on the solar wind dynamics. While the effects of turbulence driven by wave interactions due to interstellar pickup ions may be negligible in the inner heliosphere, turbulence driven by Alfvenic fluctuations and stream shear interactions may contribute significantly to solar wind acceleration beyond the Alfvenic point. We have developed a three-dimensional time-dependent MHD model of the background solar wind driven by empirical boundary conditions (i.e., WSA coronal model) coupled with a turbulence transport model. We present the model results at various heliocentric distances and along spacecraft trajectories (e.g., Earth, Parker Solar Probe, Ulysses, Venus).