Abstract
The charge state composition of the solar wind carries information about
the electron temperature, density, and velocity of plasma in the solar
corona that cannot always be measured with remote sensing techniques,
due to limitations in instrumental sensitivity and field of view as well
as line of sight integration issues. However, in-situ measurements of
the wind charge state distribution only provides the end result of the
solar wind evolution from the source region to the freeze-in point. By
using 3D global modeling it is possible to follow solar wind plasma
parcels of different origin along the path of their journey and study
the evolution of their charge states as well as the driving physical
processes. For this purpose, we implemented non-equilibrium ionization
calculations within the Space Weather Modeling Framework’s Solar Corona
and Inner Heliosphere modules, to the Alfvén Wave Solar Model
(SWMF/AWSoM). The charge state calculations are carried out parallel to
the AWSoM calculations, including all the elements and ions whose
ionization-recombination rates are included in the CHIANTI database,
namely from H to Zn. In this work, we describe the implementation of the
charge state calculation, and compare simulation results to in-situ
measurements from the ACE and Ulysses spacecraft, and study charge state
evolution of plasma parcels along different wind trajectories and wind
types.