Dynamics in solar prominences - connecting from small to large scale

最近的空间太阳任务，日本的日出使命和美国宇航局太阳动力学观测站（SDO）的使命，提供了惊人的观察静止的等离子体（冷-8000 K-云部分电离的等离子体漂浮在1兆千分之一的太阳日冕）揭示他们是高度动态的现象，磁化等离子体的基本过程是不断显示。举一个具体的例子，最令人兴奋的发现之一是磁瑞利-泰勒不稳定性，当稠密流体在轻流体上方时，边界受到扰动，导致形成上升和下降的羽流，这种不稳定性就会增加。由于驱动这些动力学的基本物理学，许多与日珥有关的关键问题的答案-即什么决定了它们何时爆发，不稳定性如何在复杂的日珥环境中增长，磁场重联如何（释放能量的磁场连通性的变化）在部分电离的日珥等离子体中工作，不同尺度之间的联系-很可能隐藏在其中。然而，日珥系统的巨大复杂性意味着我们仍然需要了解这些美丽的结构，即日珥。最近在计算能力，理论建模和发射新的NASA卫星界面区域成像光谱仪（IRIS）方面的进展-具有高灵敏度和分辨率-意味着我们现在有工具来解决与这个复杂系统有关的问题。使用一个国家的最先进的代码，同时解决了中性粒子和离子的动力学在部分电离等离子体系统的两种流体之间的相互作用，使突出的等离子体可以正确地跟踪。控制日珥系统的基本物理学的模拟将用这个部分电离的等离子体代码进行，结果与观测数据进行比较和对比，让理论和观测相互指导。通过使用所有可用工具的反馈方法，我们可以对突出系统进行新的和令人兴奋的理解。拟议的工作有一些关键目标，将被调查：1）MHD不稳定性如何（特别是磁Rayleigh-Taylor不稳定性）在静止日珥中形成。2）小空间和时间尺度上的不稳定性的存在如何影响较长时间尺度和较大空间尺度上的日珥系统，这些过程的观测特征是什么？它们与日珥爆发有什么关系？控制部分电离日珥物质中磁场重联的基本物理学是什么？4）我们如何将观测到的动力学现象与日珥系统的复杂物理学联系起来。这项研究将在剑桥大学应用数学和理论物理系（DAMTP）进行。在这个项目中，我将从理论和观测的角度研究观测到的日珥动力学的广泛范围。因此，有必要使用各种技术，从日珥不稳定性形成的大规模数值模拟到分析太阳等离子体发射的光谱线，以确定日珥中的等离子体运动。DAMTP的高级工作人员在我学习所需的广泛领域拥有丰富的经验。海伦·梅森博士和G.德尔赞纳是太阳光谱观测领域的世界领导者。M.普罗克特、J. Papaloizou和G. Ogilvie在通过大规模数值模拟研究天体物理系统方面经验丰富。所有这些联合收割机使DAMTP成为一个完美的地方，可以得到我工作所需的全面支持。

Recent space based solar missions, the Japanese Hinode mission and the NASA Solar Dynamics Observatory (SDO) mission, have provided breathtaking observations of quiescent prominences (cool - 8000K - clouds of partially ionised plasma floating in the 1MK solar corona) revealing them to be highly dynamic phenomena where the fundamental process of a magnetised plasma are on constant display. To provide a specific example, one of the most exciting discoveries is that of the magnetic Rayleigh-Taylor instability, an instability that grows when a dense fluid is above a light fluid and the boundary is perturbed resulting in the formation of rising and falling plumes. Due to the fundamental physics that drive these dynamics, the answers of many of the key questions relating to prominences - i.e. what determines when they erupt, how do instabilities grow in the complex prominence environment, how does magnetic reconnection (the change in connectivity of a magnetic field that releases energy) work in the partially ionised prominence plasma, what are the connections between the different scales in prominences - are likely to be hidden within them. However, the great complexity if the prominence system has meant that we are still to understand these beautiful structures known as prominences.Recent advances in computational power, theoretical modelling and the launch of the new NASA satellite the Interface Region Imaging Spectrograph (IRIS) - with its high sensitivity and resolution - mean that we now have the tools to tackle the problems relating to this complex system. Using a state-of-the-art code which simultaneously solves the dynamics of the neutrals and the ions in a partially ionised plasma system the interaction between the two fluids that make up the prominence plasma can be correctly tracked. Simulations of the fundamental physics that control the prominence system will be performed with this partially ionised plasma code, with the results compared and contrasted to the observational data to let theory and observations guide each other. Through this feedback approach employing all the tools that are available to use, we can head towards a new and exciting understanding to the prominence system.The proposed work has a number of key aims that will be investigated:1) How do MHD instabilities (in particular the magnetic Rayleigh-Taylor instability) form in quiescent prominences.2) How does the presence of instabilities on small spatial and temporal scales effect the prominence system on longer timescales and larger spatial scales, what are the observational signatures of these processes and how do they relate to prominence eruptions.3) What are the basic physics that controls the reconnection of magnetic fields in the partially ionised prominence material across the many observable scales.4) How can we connect between the dynamic phenomena observed and the complex physics of the prominence system. This research would take place at the Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge. In this project, I will investigate the wide range of observed prominence dynamics from both a theoretical and observational perspective. Therefore, the use of a wide range of techniques, from large-scale numerical simulations of the formation of instabilities in a prominence to the analysis of the spectral lines emitted by solar plasma to determine the plasma motion in the prominence, will be necessary. The senior staff at DAMTP have great experience in a wide range of areas required for my study. Drs. Helen Mason and G. Del Zanna are world leaders in the field of solar spectral observations and Profs. M. Proctor, J. Papaloizou and G. Ogilvie are greatly experienced in the study of astrophysical systems through large-scale numerical simulations. All these combine to make DAMTP the perfect place to be to get the full support necessary for my work.