Description
Many space weather forecasting and scientific applications would benefit from improved extrapolation of the solar coronal magnetic field, since this acts as the main “boundary condition” for models of the heliospheric magnetic field and solar wind. I will present a practical extension to the PFSS (potential field source surface) model to incorporate an axisymmetric solar wind. A steady state is obtained by balancing magnetic relaxation against the opening effect of the solar wind outflow. Perhaps surprisingly, but thanks to the axisymmetric flow, the problem is susceptible to an efficient eigenfunction/spectral treatment similar to that used in our PFSS solver (“pfsspy”), so remains practical for “real-time” forecasting. Preliminary exploration shows that the model removes the artificial source surface, leading to more realistic coronal streamer morphologies. It also enhances the open flux in a time-dependent way, partially addressing the well-known “open flux problem”.
