77th Annual Meeting of the APS Division of Fluid Dynamics (November 24, 2024 — November 26, 2024)

P2682272: Modeling Switchbacks in the Solar Wind

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Authors

• Maile Marriott, University of Texas at Austin
• Anna Tenerani, University of Texas at Austin

DOI: https://doi.org/10.1103/APS.DFD.2024.GFM.P2682272

A key question in solar physics is what heats the corona of the sun above a million degrees and what accelerates and heats the solar wind as it expands in interplanetary space. There is mounting evidence to suggest the source of energy for this extra heating is the magnetic field itself. However, the processes that transfer the heat from the magnetic field to the particles are still under investigation. The NASA Parker Solar Probe and Solar Orbiter missions have given evidence that a phenomenon called switchbacks likely play a key role in this heating. The defining characteristic of a switchback is a kink in the magnetic field, and even a complete reversal, so the field lines point sunward.The sun, corona, and the solar wind are made of plasma, the most common state of matter in the universe. Because plasma contains a large number of electrically charged particles, describing it requires not only classical mechanics, but also electromagnetism. A common way to model plasma is through Magnetohydrodynamic (MHD) simulations, which combine the equations for electromagnetism (magneto-) and fluid dynamics (--hydrodynamic). These images are from an MHD simulation of a kinked magnetic field, mimicking a switchback. Since the solar wind is a plasma, the flow is connected to the magnetic field and follows this kinked path, like water following the wave of energy as it moves towards the seashore.The colored background shows the magnetic field. Light blue is where the magnetic field is negative (pointing sunward), while the green is where the field is strongly positive.) The switchback decays over time, unfolding and losing its negativity. This generates heat and may speed up the flow of the plasma.