Authors: Roberto Lionello (PSI), Cooper Downs (PSI), Jon A. Linker (PSI), Emily I. Mason (PSI), Pete Riley (PSI)

The Time-Dependent Corona and Heliosphere

Roberto Lionello

The coupled solar-corona and heliosphere system is recognized to be essentially dynamic. This applies not only to eruptive events like coronal mass ejections or jets, but also to the slow solar wind, which is thought to originate through topological changes (i.e., interchange reconnection) at the boundary of coronal holes.
To investigate such processes, a time-dependent MHD model of coronal evolution is necessary: our newly developed method uses surface magnetic maps with flux emergence and cancellation and may introduce magnetic shear/twist (Lionello et al., 2023). We applied it to make a live prediction of the 2024 solar eclipse (Downs et al., 2025).
We have propagated the results of these coronal calculations from the outer boundary of the corona to 230 Rs. We can now show how time evolution impacts (and, sometimes, radically changes) the structure of the heliosphere, how disturbances are propagated through the solar wind, and how magnetic connectivity is always evolving. We have compared results from the time-dependent model with those obtained with the steady-state MHD model and with in-situ measurements. In particular, only the time-dependent calculation provides magnetic connectivity compatible with strahl measurements.