Authors: Zhenguang Huang (University of Michigan), Gabor Toth (University of Michigan), Nishtha Sachdeva (University of Michigan), Lulu Zhao (University of Michigan), Bart van der Holst (University of Michigan), Igor Sokolov (University of Michigan), Ward B. Manchester (University of Michigan), and Tamas I. Gombosi (University of Michigan)

The energy deposition rate into the solar atmosphere is critical in determining the solar wind acceleration and terminal velocity. However, this quantity is difficult to observe and has a large uncertainty. Sokolov et al. (2013) suggested that the ratio of the Alfven wave energy density to the magnetic field strength (at the surface of the Sun), which is called the Poynting flux parameter hereafter, can be  approximated as 1.1 MWm^-2T^-1 based on the Hinode observations by De Pontieu et al. (2007). Recently, Huang et al. (2023) used the Alfven Wave Solar atmosphere Model (AWSoM) to simulate different phases of the last solar cycle. They found that the required the Poynting flux parameter must be adjusted based on the area of the open field regions, so that the simulated solar wind can best match the OMNI solar wind observations. Moreover, the average Poynting flux parameter, which can be interpreted as the energy deposition rate for the model, is approximately constant in the open field regions in the last solar cycle. This new discovery needs to be validated with observations and can shed light on how Alfven wave turbulence accelerates the solar wind during different phases of the solar cycle.