Characterizing coronal structure: Combining remote sensing observations with global MHD modeling to make predictions for Parker Solar Probe and Solar Orbiter missions

As the solar plasma flows out from the corona and transitions into the solar wind, it transforms from a magnetically structured, subsonic, and sub-Alfvénic regime into a supersonic and super-Alfvénic flow dominated by hydrodynamics. Recent analysis of remote imaging observations in solar minimum conditions by DeForest et al. (2016) have described the early stages of this transition. Here we extend this analysis to global magnetohydrodynamics simulation of the corona and solar wind based on inner boundary conditions that emulate solar minimum, in anticipation of the first phase of Parker Solar Probe (PSP) observations, which are expected during solar minimum as well. Taken together with the imaging analysis, the simulation results provide more detailed expectations for locations of the Alfvén critical surface and the first plasma beta unity surface moving from the corona into the dynamically active solar wind. The turbulence parameters computed from the simulations also enable estimations of the characteristic scales at which in-situ turbulence may influence the dynamics of the solar wind. Estimations of relevant parameters along a simulated PSP trajectory is presented. This multi-faceted approach may be useful in the context of the upcoming Parker Solar Probe and Solar Orbiter missions, which will explore, for the first time, this transition in the inner heliosphere.