Fundamentals and Implications of Interstellar Turbulence

AST0307869Lazarian星系的星际介质（ISM）在其外观，演化和所有属性中起着至关重要的作用。因此，ISM的性质和许多过程都是由搅动它的磁湍流决定的。该计划的重点是研究星际湍流的基本原理及其含义。湍流中最基本的过程是能量向小尺度的级联。Alexandre Lazarian博士将在典型的星际环境中研究这一过程，在这种环境中，能量源在空间和时间上都是本地化的。将研究这一过程对流入分子云内部团块的演变以及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。最近在理解MHD湍流方面的进展促使Lazarian博士探索这种新的见解对宇宙射线和带电粒子动力学的影响。飞行员计算表明，预期的变化是戏剧性的，其后果不仅对星际介质，而且对天体物理学的其他分支产生广泛的影响。该研究小组（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延续），（B）开发了数值工具和专门知识来处理湍流引起的复杂问题。预期的合作将加强现有的基础设施的研究，加速它，并将提供一个刺激的环境，为研究生的智力发展。这些努力将与预测的观测测试齐头并进。为此，该小组将使用和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，建立不同星际阶段的拓扑结构，并确定湍流各向异性。工作完成后，该小组将向天体物理界提供这些工具。完成的项目将提高对星际湍流基本特性的理解，并将开发新的工具来比较理论和观测。结果将对邻近领域产生广泛影响，因为许多天体物理过程（例如ISM的加热、星星形成、热量和质量传递）取决于星际湍流的性质。*

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.***