Speaker
Description
Solar wind at L1 is modelled through a coupling of two independent and agnostic domains of the corona and heliosphere. The transition between the two domains occurs when the solar wind becomes supersonic and super-Alfvenic. The heliospheric solar wind is then be driven with appropriate boundary conditions at 0.1 AU which are derived from a coronal model. A popular choice for defining the boundary conditions using the Wang-Sheeley-Arges (WSA) model, which provides magnetic field from a potential model and estimates solar wind velocity through an empirical relationship with the coronal magnetic field.
However, while phenomena such as coronal mass ejections are time-dependent features, they are often simulated in a background wind that is quasi-steady and driven by a single WSA map or “snapshot” of the Sun. Such steady-state simulations don't capture the evolving nature of the Sun and discard information from previous time steps. In this study, we present results from a 2.5D magnetohydrodynamic (MHD) simulation of the heliosphere in the equatorial plane to assess the importance of incorporating the time-dependent boundary conditions on solar wind parameters in the heliosphere by driving simulation using time-evolving WSA maps.
We find that the movement of the heliospheric current sheet (HCS) around the equatorial plane drives reconnection, particularly during periods of high solar activity. We then inject monochromatic Alfven waves at the 0.1 AU boundary to study wave propagation in the heliospheric wind. Finally, we compare the forecasted wind parameters at L1 in a time-dependent simulation as compared to a steady-state simulation.
