Modeling the Solar Wind During Different Phases of the Last Solar Cycle

TL;DR

This study systematically simulates the solar wind across different solar cycle phases using the AWSoM model, focusing on optimizing the Poynting flux parameter and its correlation with magnetic field properties.

Contribution

It identifies the optimal Poynting flux parameter values and their strong correlations with magnetic field characteristics, improving solar wind modeling accuracy.

Findings

Optimal Poynting flux correlates with open magnetic field area (r=0.96).

Poynting flux in open regions remains approximately constant over the cycle.

Strong anti-correlation between Poynting flux and average unsigned radial magnetic field (r=-0.91).

Abstract

We describe our first attempt to systematically simulate the solar wind during different phases of the last solar cycle with the Alfv\'en Wave Solar atmosphere Model (AWSoM) developed at the University of Michigan. Key to this study is the determination of the optimal values of one of the most important input parameters of the model, the Poynting flux parameter, which prescribes the energy flux passing through the chromospheric boundary of the model in the form of Alfv\'en wave turbulence. It is found that the optimal value of the Poynting flux parameter is correlated with the area of the open magnetic field regions with the Spearman's correlation coefficient of 0.96 and anti-correlated with the average unsigned radial component of the magnetic field with the Spearman's correlation coefficient of -0.91. Moreover, the Poynting flux in the open field regions is approximately constant in the last solar cycle, which needs to be validated with observations and can shed light on how Alfv\'en wave turbulence accelerates the solar wind during different phases of the solar cycle. Our results can also be used to set the Poynting flux parameter for real-time solar wind simulations with AWSoM.