High-Resolution Simulations of CME-Solar Wind Interaction in The Heliosphere: A Focus On Mesoscale Structures For PUNCH

Understanding mesoscale structures in the solar wind background and coronal mass ejections (CMEs) is one of the science objectives of the PUNCH mission to be launched in early 2025. We do not fully understand what processes form these structures and where as well as how they evolve from the outer solar corona through the heliosphere. In anticipation of the detailed high-sensitive large field-of-view PUNCH imaging, MHD simulations capable of modeling the global inner heliosphere while simultaneously resolving structures at mesoscales can help predict what structures we can expect to form in certain CME-solar wind interaction scenarios. We use an efficiently parallelized and scalable physics-based MHD model with numerical algorithms featuring high resolving power to perform global inner heliosphere simulations with CMEs with a high resolution. Using the GAMERA-Helio inner heliosphere model coupled with the Gibson-Low CME model, we model the evolution of a wide and fast CME flux rope through a realistic solar wind background. The simulation resolves spatial scales down to ~0.1 solar radii (~10 Earth radii), enabling, to study mesoscale structures that form in the CME-solar wind interaction in a global context. We discuss the development of ripples and irregularities at the CME shock, compressions, and magnetic field fluctuations in the CME-driven sheath, and connect these structures with the interaction between the CME and background solar wind flows. By computing the total and polarized white light brightness from high-resolution GAMERA MHD simulations, we show how mesoscale structures that form at the CME-solar wind interface appear in synthetic images in the FOV of the PUNCH mission.