Turbulence Transport in Sub-Alfvenic and Subsonic Astrophysical Plasma Flows

通过拟议的3年研究项目，我们打算加强德国波鸿鲁尔大学与新西兰汉密尔顿怀卡托大学之间的成功合作，该合作是最近在一项为期一年的DFG专项资助框架内启动的，主题是日光层和天体层的耦合等离子体流体和湍流传输建模。拟议研究项目的主要目标是：㈠定量评估太阳风和其他恒星风的外亚阿尔夫文和亚音速区域中湍流的传输情况; ㈡定量研究由此产生的高能粒子的传输情况。因此，该项目的主要目标是回答以下三个关于湍流演化以及传输过程和相应的传输方程的科学关键问题：（1）如何在多分量模型框架内定量描述部分亚阿尔夫文和亚音速内日鞘（太阳风终止激波和日球顶之间）和恒星星鞘（恒星风终止激波和弓形激波之间）中的湍流传输？(2)内日鞘和恒星星鞘中的湍流演化如何影响宇宙线输运参数的时空变化？（3）用新的可压缩湍流模型求输运参数时，宇宙线输运方程的解是什么？通过实现这个及时的项目的目标，我们不仅将补充急需的湍流演化模型与一个新的，三个组成部分的描述，第一次，将允许同时和自洽的处理准二维，波浪状，以及压缩波动，但我们也将建立一个大大改进的概念框架，用于模拟高能粒子在内日鞘和外日鞘中的传输条件。恒星鞘鉴于最近旅行者号航天器在日鞘中进行的和正在进行的现场测量，以及天体层对宇宙射线加速和宇宙射线各向异性的潜在重要性，这两种传输环境都引起了太阳物理学界和天体物理学界的高度兴趣。

With the proposed 3-year research project we intend to intensify the successful collaboration between the Ruhr-Universität of Bochum, Germany, and the University of Waikato, Hamilton, New Zealand, that was recently initiated within the framework of a dedicated 1-year DFG funding on the topic of coupled plasma fluid and turbulence transport modelling of the heliosphere and of astrospheres. The main goals of the proposed research project are (i) a quantitative assessment of the transport of turbulence in the outer sub-Alfvenic and subsonic regimes of the solar wind and other stellar winds, and (ii) a quantitative study of the resulting transport of energetic particles. Consequently, the primary objective of the project is the answering of the following three scientific key questions regarding the turbulence evolution as well as the transport processes and the corresponding transport equation:(1) How can the transport of turbulence in the partially sub-Alfvenic and subsonic inner heliosheath (between the solar wind termination shock and the heliopause) and in stellar astrosheaths (between the stellar wind termination shocks and the bow shocks) be described quantitatively within the framework of a multi-component model?,(2) How does the turbulence evolution in the inner heliosheath and in stellar astrosheaths influence the spatial and temporal variation of the transport parameters of cosmic rays?, and (3) What are the solutions of the cosmic ray transport equation when using the new compressible turbulence model to obtain the transport parameters?By attaining the goals of this timely project we will not only supplement the much needed models of turbulence evolution with a new, three-component description that, for the first time, will allow for a simultaneous and self-consistent treatment of quasi-twodimensional, wave-like, as well as compressive fluctuations, but we will also establish a significantly improved conceptual framework for the modelling of the transport conditions of energetic particles in both the inner heliosheath and in stellar astrosheaths. In view of the recent, and ongoing, in-situ measurements made in the heliosheath by the Voyager spacecraft and the potential importance of astrospheres for cosmic ray acceleration and cosmic ray anisotropies, both transport environments are of high contemporary interest for the helio- and astrophysics communities.