Global Multi-Fluid Solar Corona and Inner Heliosphere Model for Solar Probe Plus and Solar Orbite

Abstract:

The mechanisms that heat and accelerate the fast and slow wind have not yet been conclusively identified, and their understanding is one of the major science goals of the Solar Orbiter (SO) and Solar Probe Plus (SPP) missions. Helium abundance and properties in the solar wind are critical tracers for both processes so that understanding them is key towards gaining insight in the solar wind phenomenon, and being able to model it and predict its properties. SO and SPP will carry critical instrumentation to measure the properties of Helium in the solar wind at distances between within 10 solar radii up to 1 AU. We present a generalization of the recently developed global solar corona and inner heliosphere model with low-frequency Alfvenic turbulence [van der Holst et al. (2014)] to include alpha-particle dynamics. This new multi-fluid model uses the stochastic heating mechanism to partition the turbulence dissipation into coronal heating of the electrons and ions. The momentum and energy exchange rates due to Coulomb collisions are accounted for. We discuss the feasibility for Alfvenic turbulence to simultaneously address the coronal heating and proton-alpha particle differential streaming.