The Quiet Sun Dynamo: Shallow versus Deep

安静的太阳发电机：浅与深

• 批准号: 1141921
• 负责人: Robert Stein
• 金额: $ 23.02万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-12-15 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1141921&HistoricalAwards=false
• 关键词: Quiet; Sun; Dynamo; Shallow; versus

The Principal Investigator (PI) will investigate the magnetodynamics of the solar surface and upper convection zone in both quiet and active regions of the Sun, in order to determine the origin of the 'quiet Sun' magnetic field. He will evaluate the relative contributions of shallow surface dynamo action and deep convection zone dynamo action, as well as establish the rate of magnetic flux emerging from these two processes, by comparing observations with calculations from dynamo and magnetoconvection simulations within a supergranule-scale portion of the solar surface. His simulations will include the distribution of vertical and horizontal magnetic field strengths, the spectrum of vertical and horizontal magnetic fields, and the variation of supergranule sizes with the solar cycle. The PI's simulations solve the non-linear, compressible, three-dimensional equations for conservation of mass, momentum, and internal energy, as well as the induction equation for the magnetic field. The PI's model uses a tabular equation-of-state to determine the Local Thermodynamic Equilibrium pressure, temperature, opacities, and source functions, as a function of log density and internal energy. The PI is motivated by the fact that the behavior of magnetic fields near the solar surface is the ultimate driver of Earth's space weather. The simulation results will be posted on multiple web sites where they will be widely available to the solar scientific community and to the general public. The PI will mentor a female collaborator at Michigan State University in the use and analysis of his simulations and observations. The simulation results from this effort will also be used to enhance a museum exhibit demonstrating how scientists use sophisticated models, now being constructed at the Lansing, Michigan "Impression 5 Science Center," which hosts over 100,000 people annually, both individually and in school groups.

首席研究员（PI）将研究太阳平静区和活跃区太阳表面和上层对流区的磁动力学，以确定“平静的太阳”磁场的起源。他将评估浅层表面发电机作用和深层对流区发电机作用的相对贡献，并通过将观测结果与太阳表面超粒子尺度部分的发电机和磁对流模拟的计算结果进行比较，确定这两个过程产生的磁通量率。他的模拟将包括垂直和水平磁场强度的分布，垂直和水平磁场的频谱，以及超颗粒大小随太阳周期的变化。PI的模拟解决了质量、动量和内能守恒的非线性、可压缩的三维方程，以及磁场的感应方程。PI的模型使用表格状态方程来确定局部热力学平衡压力、温度、不透明度和源函数，作为对数密度和内能的函数。太阳表面附近的磁场行为是地球空间天气的最终驱动因素，这一事实促使了PI的产生。模拟结果将发布在多个网站上，供太阳科学界和公众广泛使用。PI将指导密歇根州立大学的一位女性合作者使用和分析他的模拟和观察结果。这项工作的模拟结果还将用于加强博物馆展览，展示科学家如何使用复杂的模型，目前正在密歇根州兰辛的“印象5科学中心”建造，该中心每年接待超过10万人，包括个人和学校团体。