Unraveling Solar Wind Variations in the Last Solar Cycle Using Global Magnetohydrodynamic (MHD) Simulations

了解太阳风的变化是太阳物理学中最重要的课题之一。太阳风是太空天气的驱动因素，影响着太空技术。该项目将研究基于Alfven波湍流的模型是否能够一致地解释整个太阳周期的日冕加热和太阳风加速。全球三维数值模式Alfven波太阳大气模式（AWSoM）将被使用，并进一步发展纳入额外的物理。这项工作还支持早期职业女性科学家、研究生和本科生。该项目使用最先进的基于物理的磁流体动力学（MHD）模型，即空间天气建模框架（SWMF）中的AWSoM，来研究AWSoM中的物理是否足以解释在上一个太阳周期中观测到的太阳风变化。将模拟的太阳风与最后一个太阳周期的各种现场太阳风观测结果进行比较，以实现科学目标。该小组将调查模拟的阿尔芬波能量密度是否与太阳周期不同阶段的观测结果一致。坡印廷通量和横向相关长度参数将发生变化，AWSoM从这些运行中生成的模拟数据将与美国宇航局任务中测量的日球层不同位置的原位数据进行比较。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding solar wind variations is one of the most important topics in heliophysics. The solar wind is a driver of space weather, which impacts space-based technology. This project will investigate whether Alfven wave turbulence-based models can consistently explain the coronal heating and solar wind acceleration throughout the solar cycle. The Global 3-D numerical model Alfven Wave Solar atmosphere Model (AWSoM) will be used and further developed by incorporating additional physics. The work also supports an early career woman scientist, graduate student, and undergraduate students.This project uses the state-of-the-art physics-based magnetohydrodynamics (MHD) model, AWSoM within the Space Weather Modeling Framework (SWMF) to investigate if the physics within AWSoM is sufficient to explain solar wind variations observed in the last solar cycle. The science objective will be achieved by comparing the simulated solar wind with various in-situ solar wind observations in the last solar cycle. The team will investigate whether the simulated Alfven wave energy densities agree with the observations during different phases of the solar cycle. The Poynting flux and transverse correlation length parameters will be varied and the AWSoM simulated data generated from these runs will be compared to in-situ data at various locations in the heliosphere, as measured by NASA missions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.