Fundamentals and Implications of Interstellar Turbulence

星系的星际介质（ISM）在星系的外观、演化和整体特性中起着至关重要的作用。反过来，ISM的性质和其中的许多过程是由搅动它的磁湍流决定的。该提案的重点是研究星际湍流的基本原理及其影响。湍流中最基本的过程是能量级联到小尺度。亚历山大·拉扎里安博士将在典型的星际环境中研究这一过程，在这种环境中，能量来源在空间和时间上都是局部的。将研究这一过程对流入分子云内团块的演变的影响，以及对宇宙射线加速的影响。磁湍流与带电粒子的相互作用是另一个由湍流性质决定的基本过程。最近对MHD湍流的理解取得了进展，这促使Lazarian博士探索宇宙射线和带电颗粒动力学的新见解。初步计算表明，预期的变化是巨大的，其后果不仅会对星际介质产生广泛的影响，而且会对天体物理学的其他分支产生影响。这个研究小组已经(a)在理解这些基本性质方面取得了实质性进展，发现了一些新的以前未知的磁湍流机制（磁级联在离子中性阻尼尺度之外的继续），并且(b)开发了数值工具和专业知识来处理湍流提出的复杂问题。预期的合作将加强现有的研究基础设施，加速研究，并将为研究生的智力发展提供一个刺激的环境。这些努力将与对预测的观测检验齐头并进。为此，该团队将使用并改进其最近开发并成功测试的统计工具。这些工具可以从数据谱线数据立方体中提取速度和密度的统计数据，建立不同星际相位的拓扑结构，并确定湍流的各向异性。这项工作完成后，该团队将把这些工具提供给天体物理学界。完成的项目将提高对星际湍流基本特性的理解，并将开发比较理论和观测的新工具。该结果将对邻近领域产生广泛的影响，因为许多天体物理过程（例如ISM的加热，恒星形成，热量和质量传递）依赖于星际湍流的性质

AST 0307869LazarianThe interstellar medium (ISM) of a galaxy plays a crucial role in its appearance, evolution, andoverall properties. In turn, the nature of the ISM and many processes within it are determinedby the magnetic turbulence that stirs it. The proposal is focused on the studies of fundamentalsof interstellar turbulence and its implications. The most fundamental process in turbulence isthe energy cascading to small scales. Dr. Alexandre Lazarian will study this process in typical interstellar environments where sources of energy are localized both in space and time. Implications of this process on the evolution of inflows onto clumps inside molecular clouds, as well as for cosmic ray acceleration, will be studied. The interaction of magnetic turbulence with charged particles is another fundamental process that is determined by the properties of the turbulence. Recent progress in understanding of MHD turbulence motivates Dr. Lazarian to explore what this new insight entails for the dynamics of cosmic rays and charged grains. Pilot calculations show that the expected changes are dramatic with the consequences that will have a broad impact not only on the interstellar medium, but also to other branches of astrophysics. This research group has (a) made substantial progress in understanding those fundamental properties, discovered some new previously unknown regimes of magnetic turbulence (the continuation of the magnetic cascade beyond the ion-neutral damping scale), and (b) has developed numerical tools and expertise to deal the complicated issues turbulence raises. Intended collaborations will enhance the available infrastructure for the research, accelerate it, and will provide a stimulating environment for the intellectual development of a graduate student. These efforts will go hand in hand with observational testing of the predictions. For this purpose, the team will use and improve statistical tools that it has developed and successfully tested recently. Those tools allow the extraction of statistics of velocity and density from data spectral line data cubes, establish topology of different interstellar phases and determine turbulence anisotropy. Upon the completion of the work, the team will make those tools available to the astrophysical community. The completed projects will improve understanding of fundamental properties of interstellar turbulence and will develop new tools for comparing theory and observations. The results will have a broad impact on adjacent fields, since many astrophysical processes (e.g. heating of the ISM, star formation, heat and mass transfer) depend on properties of interstellar turbulence.***