Advective Flux Transport Model

Source: SolarCycleScience.co

The Advective Flux Transport (AFT) model is an advanced representation of the Surface Flux Transport (SFT) process, which describes the movement of magnetic flux on the Sun's surface. This model is crucial for understanding the latter stages of the solar dynamo process, where surface flows transport magnetic flux from active regions to the Sun’s poles. During this process, the polar fields from the previous solar cycle are canceled out, and a new poloidal field of opposite polarity begins to form, setting the stage for the next solar cycle.

The AFT model stands out by minimizing parameterizations and directly incorporating observed data on active regions and surface flows. Unlike previous models that relied on artificial insertion of active regions and simplified flow profiles, the AFT model uses measured axisymmetric flows and a convective simulation that replicates the spectral characteristics of the Sun’s convective flows. This method allows for a more realistic simulation of surface flows, considering the finite lifetimes of convective cells and their interactions with differential rotation and meridional flow. Additionally, the AFT model accounts for the dampening effect of strong magnetic fields on convective velocities, a feature that traditional diffusivity-based models struggle to replicate.

By incorporating magnetic data through manual insertion or direct assimilation from magnetograms, the AFT model achieves high flexibility and accuracy. Manual insertion, based on active region databases like NOAA, allows the model to explore flow dynamics and make predictions, while data assimilation ensures the most accurate synchronic maps of the Sun. These maps form the Baseline data set, which is essential for evaluating SFT models and providing source data for models extending into the solar atmosphere and heliosphere. The AFT model’s approach marks a significant improvement in the realism and accuracy of solar surface flow simulations.