Planetary Mantle Dynamics

太阳系中类地行星的热量损失是由其外层硅酸盐外壳中的对流控制的。在地球上，这种对流表现为板块构造和由此产生的大陆漂移。这项提议中包含的研究将侧重于行星内部的热演化以及表面和内部动力学之间的反馈。该方法将侧重于利用包含在自重球壳或平面层系统中的二维和三维对流流体的计算机模型。大量拟议活动的动机来自于观察到地球是太阳系中唯一具有板块构造的行星，以及我们想要了解为什么会这样。感兴趣的具体专题将包括审查系统几何结构(即地幔厚度)，特别是行星核大小对地幔对流热特性的影响。此外，我们还将研究活动表面对地幔对流的影响以及板块运动的物理要求。通过研究流体参数(如热粘性)对对流特性的影响，将探索岩石行星和结冰卫星热演化的本质。此外，大陆和深化学上不同的异常可能在行星热演化中发挥的作用将推动拟议工作的一部分。还将研究将这些模型和应用扩展到太阳系外行星的情况。 通过利用在分布式存储器并行计算平台上运行的复杂计算模型(即，利用多个处理器)来促进该研究。目前，一个由四名研究生组成的小型行星内饰小组在我的指导下在多伦多大学斯卡伯勒分校(UTSC)工作，并受益于对本网站通用计算(GPC)集群的访问。在过去的五年里，该研究小组已经将我们研究中使用的所有计算机代码移植到了本网络的GPC上。因此，这里提出的研究所需的所有工具都已可用、经过测试并可随时使用。此外，我们现在正在利用UTSC开发的代码以及从合作项目中获得的新计算机代码，这些代码非常适合利用本网络的能力。这将使这里描述的研究项目能够在以前无法获取的制度和时间尺度上探索身体行为。例如，现有的代码和高性能计算设施将允许UTSC的研究人员对具有对流活力和类地行星表面积的系统中的行星对流进行建模，模拟数十亿年的演化。 所有这些研究的基本主题都是研究行星热损失和地表运动的时间依赖性。所涉及的研究将培训高素质的人员(HQP)，以使用高性能计算来研究地球物理流体动力学问题。为了开展这些项目，需要为六名研究人员提供支持。在接下来的五年里，这一群体的总体构成将包括首席研究员、一名博士后研究助理和四名同时攻读硕士和博士学位的研究生。这些HQP将参与因使用研究所需的计算工具而产生的国际合作研究。资金将支持完成6个博士学位和4个硕士学位，总部基地将完成他们的研究项目，获得经验，其中将包括作为地球动力学家的培训和接触传播科学成果的方法。

Heat loss from the terrestrial planets in our solar system is governed by convection in their outer silicate shells. In the case of the Earth, this convection is manifested as plate tectonics and the continental drift that results. The research encompassed in this proposal will focus on the thermal evolution of planetary interiors and the feedback between surface and interior dynamics. The methodology will focus on utilizing computer models of two- and three-dimensional convecting fluids contained within either self-gravitating spherical shells or plane-layer systems. Motivation for a substantial amount of the proposed activity derives from the observation that the Earth is the only planet in the solar system featuring plate tectonics and our desire to understand why this is so. Specific topics of interest will include examining the influence of system geometry (i.e., mantle thickness) and particularly planetary core size on the thermal character of mantle convection. In addition, we shall investigate the influence of a mobile surface on mantle convection as well as the physical requirements for plate motion. The nature of the thermal evolution of rocky planets and icy moons will be explored by investigating the influence of fluid parameters (e.g., thermal viscosity dependence) on convection characteristics. Moreover, the role in planetary thermal evolution that may be played by continents and deep chemically distinct anomalies will drive a portion of the proposed work. Extension of the models and applications to exosolar planets will also be examined. The research is facilitated by utilizing sophisticated computational models run on distributed memory parallel computing platforms (i.e., utilizing many processors). Presently, a small planetary interiors group of four graduate students works under my guidance at the University of Toronto-Scarborough (UTSC) and benefits from access to the SciNet General Purpose Computing (GPC) Cluster. Over the past five years the research group has migrated all of the computer codes used for our research to SciNet's GPC. Consequently, all tools required for the research proposed here are already available, tested and ready to use. In addition, we are now utilizing codes developed at UTSC as well as new computer codes, obtained from collaborative ventures that are well suited to capitalize on SciNet's capabilities. This will enable the research projects described here to probe physical behaviour in regimes, and on time-scales, not previously accessible. For example, the codes and high performance computing facilities now available will allow researchers at UTSC to model planetary convection in systems featuring both the convective vigour and the surface area of an Earth-like planet over periods simulating billions of years of evolution. The underlying theme of all of these studies is investigation of the time-dependence of planetary heat loss and surface motion. The research involved will train highly qualified personnel (HQP) in the use of high performance computing for investigating problems in geophysical fluid dynamics. To undertake these projects , support for a group of six researchers is sought. Over the next five years, the general makeup of this group will include the Principal Investigator, a post-doctoral research assistant and four graduate students, engaged in both MSc and PhD studies. These HQP will be engaged in international collaborative research stemming from use of the computing tools required for the research. Funding would support the completion of six PhD and four MSc degrees and the HQP will complete their research projects having obtained experience that will include training as geodynamicists and exposure to the methods by which scientific results are disseminated.