CDI-Type I: Combined Global Physical, Chemical, and Mineralogical Models of Protoplanetary Disks

地球在已知行星中是独一无二的，因为它的表面有液态水，这是生命存在的关键原因。解释这一现象的原因，并预测其他地方适合生命生存的条件，需要了解地球和其他行星形成的原行星盘，这是一个由年轻太阳轨道上的岩石、尘埃、气体、等离子体和磁场组成的复杂、相互作用的系统。不同科学界的许多模型都解决了这个问题的不同方面，但没有一个模型将所有不同的物理、化学和矿物学过程集成到一个单一的、通用的、不断改进的三维计算模型中。我们即将进入千万亿级计算时代，使这样的模型第一次实用。该项目将是在全球模拟原行星盘的基础上开发完整的多物理模型的第一次认真尝试。我们将包括三个主要的物理过程。首先是与部分电离气体耦合的磁场驱动的湍流，它决定了圆盘附着在恒星上的速度，以及尘埃能多好地粘在一起形成行星的积木。其次是磁盘的辐射冷却，这决定了磁盘的温度，并由磁盘的灰尘程度决定。反过来，这在一定程度上是由温度控制的。第三，气体的化学成分和温度以及尘埃的性质决定了气体的电离，而电离又决定了圆盘的湍流程度。所有这些过程都将包括在一个共同的计算框架中。这一框架将依赖于一种新的数值算法来计算磁化气体流动，该算法使用模拟的粒子与气体一起运动。该算法结合了传统的基于网格的模拟程序和更广泛使用的粒子方法(如平滑粒子流体力学)的优点和局限性。我们的团队包括这种方法的发明者。有了一个新的综合模型，我们将能够更好地了解地球的位置和性质，其他太阳系天体的性质，以及太阳系外行星系统的观测。这个项目的资金将支持在这里治疗的流星学和天体物理领域的研究生的跨学科培训。主办机构和两个欧洲机构之间的合作将得到支持，研究生将双向旅行进行合作和培训。三名本科生也将参与这项研究。在这里进行的研究将为PI和共同PI Ebel的展览和教育工作提供参考。目前，他们的项目包括一个新的海登天文馆太空展(估计在5年内有700万国际观众，其中包括50万纽约市学童)，一个关于卡西尼-惠更斯土星任务的图片展，以及与博物馆的专业发展和社区教育部门的广泛工作，以及指导夏季REU学生和实习生。

The Earth is unique among known planets in having liquid water on its surface, a crucial reason for the existence of life. Explaining how this came to be, and predicting conditions friendly to life elsewhere requires understanding the protoplanetary disk from which Earth and the other planets formed, a complex, interacting system of rocks, dust, gas, plasma, and magnetic fields in orbit around the young Sun. Many models by different scientific communities have addressed separate aspects of this problem, but none has integrated all the different physical, chemical, and mineralogical processes into a single, general, continuously improvable, three-dimensional, computational model.Our imminent entry into the petascale computing era makes such a model practical for the first time. This project will be the first serious attempt to develop a complete, multi-physics model based on a global simulation of a protoplanetary disk. We will include three major physical processes. First is the turbulence driven by magnetic fields coupled to the partially ionized gas, which determines how fast the disk accretes onto the star and how well dust can stick together to form the building blocks of planets. Second is the radiative cooling of the disk, which determines the temperature of the disk, and is determined by how dusty the disk is. That, in turn, is controlled partly by the temperature. Third, the gas chemistry and the temperature, as well as the dust properties, determine the ionization of the gas, which in turn determines how turbulent the disk is. All of these processes will be included in a common computational framework. This framework will rely on a novel numerical algorithm for computing magnetized gas flows using simulated particles moving with the gas. This algorithm combines advantages and evades limitations of both traditional grid-based simulation codes and of more widely used particle methods such as smoothed particle hydrodynamics. Our team includes the inventor of this method.With a new, integrated model, we will be able to better understand Earth's position and properties, the properties of other Solar System objects, and observations of extrasolar planetary systems.The funding for this project will support the interdisciplinary training of a graduate student in the areas of meteoritics and astrophysics treated here. A collaboration between the host institution and two European institutions will be supported, with graduate students traveling in both directions for collaboration and training. Three undergraduate students will also participate in this research.The research undertaken here will inform the exhibitions and education work of the PI and co-PI Ebel. Currently, their projects include a new Hayden Planetarium Space Show (estimated international viewership 7 million over 5 years, including 0.5 million NYC school children), a photo exhibit on the Cassini-Huygens mission to Saturn, as well as extensive work with the professional development and community education departments of the Museum, and mentoring summer REU students and interns.