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arXiv · 2306.11956

Time-Dependent Dynamics of the Corona

Emily I. Mason·Roberto Lionello·Cooper Downs·Jon A. Linker·Ronald M. Caplan
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Abstract

We present in this Letter the first global comparison between traditional line-tied steady state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. The maps are scaled to the approximate field distributions and magnitudes around solar minimum using the Lockheed Evolving Surface-Flux Assimilation Model to incorporate flux emergence and surface flows over a full solar rotation, and include differential rotation and meridional flows. Each time step evolves the previous state of the plasma with a new magnetic field input boundary condition. We find that this method is a significant improvement over steady-state models, as it closely mimics the constant photospheric driving on the Sun. The magnetic energy levels are higher in the time-dependent model, and coronal holes evolve more along the following edge than they do in steady-state models. Coronal changes, as illustrated with forward-modeled emission maps, evolve on longer timescales with time-dependent driving. We discuss implications for active and quiet Sun scenarios, solar wind formation, and widely-used steady state assumptions like potential field source surface calculations.

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Emily I. Mason, Roberto Lionello, Cooper Downs, Jon A. Linker, Ronald M. Caplan. 2023-06-21. Time-Dependent Dynamics of the Corona. https://arxiv.org/abs/2306.11956

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