Speaker
Description
It has been shown that MHD time-dependent (TD) solar wind simulations provide more accurate predictions in the inner heliosphere compared to commonly used steady state ones. This is because, in the TD approach, we approximate the evolution of the solar corona by frequently updating the magnetograms and thus the inner heliospheric boundary conditions at 0.1 au. The resulting dynamic solar wind in the heliosphere is, therefore, more realistic compared to the overly idealized solar wind in the steady state approach. A significant issue that modelers face when working with TD simulations is the formation of artifacts that appear in the heliosphere due to abrupt magnetic field changes between consecutive magnetograms (e.g., when an active region (AR) emerges from the non-visible side of the Sun from one moment to another). This problem affects all TD MHD solar wind efforts in the community and is manifested by sudden jumps/changes in the shape of the heliospheric current sheet (HCS) from one time step to another, but also as abrupt changes of velocities in the heliosphere. In this study, we use the coupled WSA model of the solar corona and the GAMERA model of the inner heliosphere for performing TD solar wind simulations. We present a quantitative analysis on how bigger or smaller changes in magnetograms from one timestamp to another affect the HCS and, as an extent, the solar wind predictions in the interplanetary space. We discuss to what extent such changes can be ignored or should be seriously taken into account and dealt with.
