Understanding the Reversals in Polarity of the Magnetic Fields of Planets and Stars

恒星和行星中的磁场是宇宙中常见的特征。然而，在所有这些不同的物体中，这些磁场的单独属性差别很大。在我们的太阳系中，太阳的磁场每22年就有一次明确的、周期性的磁极反转。相比之下，地球经历的磁场极性反转在时间上是不规则的。太阳系中除火星和金星外的所有行星都有活跃的磁场，而火星曾经是一个相对较强的磁场之家。在其他恒星中也观察到了磁场。对磁场极性反转原因的研究可以产生影响太阳耀斑预测的结果，以及了解将影响人类在地球轨道以外进行探索的空间环境。研究人员将开发和使用新的软件工具，以促进我们对极性反转的理解。首席研究员和一名研究生将领导这一项目，这也将为本科生提供许多加入研究的机会。研究人员将开发新的发电机建模分析工具，并将它们整合到一个易于理解的高效磁流体程序中，以促进我们对新动力体制中的极性反转的理解。这些工具将允许对极性反转进行多尺度分析，并能够准确描述在迄今观察到的两个反转制度中起作用的物理过程。这项研究有可能通过对支配自然发电机的方程式进行迄今为止最详细的数值分析之一，显著改变目前对发电机物理学的看法。

Magnetic fields in the stars and planets are common features in the universe. The individual properties of these magnetic fields vary widely, however, among all of these different objects. In our own Solar System, the Sun's magnetic field has a well-defined, periodic reversal of polarity every 22 years. In contrast, the Earth undergoes magnetic field polarity reversals that are irregular in timing. All planets in the Solar System except Mars and Venus have active magnetic fields, and Mars was once home to a relatively strong magnetic field. Magnetic fields have also been observed in other stars. Research into the causes of magnetic field polarity reversals can produce results affecting the forecasting of solar flares, as well as understanding the space environment that will affect human exploration beyond the Earth's orbit. The investigators will develop and use new software tools to advance our understanding of polarity reversals. The Principal Investigator and a graduate student will lead this project, which will also make many opportunities for undergraduates to join in the research.The investigators will develop novel dynamo modeling analysis tools and incorporate them into a well-understood and highly efficient magnetohydrodynamic code to advance our understanding of polarity reversals in new dynamical regimes. These tools will allow for a multiscale analysis of polarity reversals, and enable a precise characterization of the physical processes at work in the two reversal regimes observed to date. This research has the potential to significantly alter the current view of dynamo physics by conducting one of the most detailed numerical analyses to date of the equations governing natural dynamos.