Fundamentals and Implications of Interstellar Turbulence

拉萨里安星系的星际介质(ISM)对它的出现、演化和所有性质都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场湍流决定的。该计划的重点是研究星际湍流的基本原理及其意义。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化的。我们将研究这一过程对流入分子云内团块的演化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由湍流性质决定的另一个基本过程。在理解MHD湍流方面的最新进展促使拉扎里安博士探索这一新见解对宇宙射线和带电粒子的动力学有何影响。试点计算表明，预期的变化是戏剧性的，其后果不仅将对星际介质产生广泛影响，还将对天体物理学的其他分支产生广泛影响。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，发现了一些以前未知的新的磁湍流机制(磁级联的延续超出了离子中性阻尼级)，(B)开发了数值工具和专业知识来处理湍流引起的复杂问题。计划中的合作将加强研究的现有基础设施，加速研究，并将为研究生的智力发展提供一个激励的环境。这些努力将与对预测的观测测试齐头并进。为此目的，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，建立不同星际相的拓扑结构，并确定湍流的各向异性。在工作完成后，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性质的理解，并将开发新的工具来比较理论和观测。这些结果将对邻近区域产生广泛的影响，因为许多天体物理过程(例如ISM的加热、恒星的形成、热量和质量转移)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.***