Fundamentals and Implications of Interstellar Turbulence

星际湍流的基本原理和影响

• 批准号: 0307869
• 负责人: Alexandre Lazarian
• 金额: $ 15.4万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0307869&HistoricalAwards=false
• 关键词: Fundamentals; Implications; Interstellar; Turbulence

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.***

AST 0307869Lazarian 星系的星际介质 (ISM) 在其外观、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。该提案的重点是星际湍流的基本原理及其影响的研究。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（Alexandre Lazarian）博士将在典型的星际环境中研究这一过程，其中能量来源在空间和时间上均局域化。我们将研究这一过程对分子云内团块流入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特性决定的另一个基本过程。最近在理解 MHD 湍流方面取得的进展促使 Lazarian 博士探索这一新见解对宇宙射线和带电颗粒动力学的意义。试点计算表明，预期的变化是巨大的，其后果不仅会对星际介质产生广泛影响，而且还会对天体物理学的其他分支产生广泛影响。该研究小组（a）在理解这些基本特性方面取得了实质性进展，发现了一些新的先前未知的磁湍流状态（磁级联超出离子中性阻尼尺度的延续），并且（b）开发了数值工具和处理动荡引发的复杂问题的专业知识。预期的合作将增强研究的可用基础设施，加速研究进程，并为研究生的智力发展提供一个刺激的环境。这些努力将与预测的观察测试齐头并进。为此，该团队将使用和改进其最近开发并成功测试的统计工具。这些工具允许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并确定湍流各向异性。工作完成后，该团队将向天体物理学界提供这些工具。已完成的项目将增进对星际湍流基本特性的理解，并将开发用于比较理论和观测结果的新工具。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、恒星形成、热量和质量传递）取决于星际湍流的特性。***