Numerical MHD models of stream interaction regions (SIRs) and corotating interaction regions (CIRs) using sunRunner3D: comparison with observations

Abstract

ABSTRACT In this work, we present numerical simulations of Stream Interaction Regions (SIRs) and Corotating Interaction Regions (CIRs) using the sunrunner3d tool that employs as a coronal model the boundary conditions obtained by corhel/mas with the pluto code that describes the global 3D structure of the solar wind using the magnetohydrodynamics (MHD) approach in the inner heliosphere. Specifically, we selected a set of SIRs and CIRs observed by the Parker Solar Probe (PSP) and STEREO-A (STA) missions during the Carrington rotations (CRs) 2207 to 2210 and CRs from 2020 to 2022. In order to describe the dynamics of the plasma that constitutes the solar wind background conditions for the selected CRs, we solve the ideal MHD equations in an inertial frame of reference, managing the solar rotation by rotating the boundary values in ϕ (longitude) at a rate corresponding to the sidereal rotation rate of the solar equator. We show that our results using sunrunner3d can globally reproduce the plasma parameters, such as radial velocity, number proton density, and radial magnetic field strength of these large-scale structures, observed by PSP and STA at distances near the Sun and around 1 au, respectively. These results allow exploring the global evolution of SIRs/CIRs in the inner heliosphere using sunrunner3d.