Towards Understanding Interstellar Turbulence

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Although turbulence is chaotic, it can be described and understood. Turbulence is governed by well-defined statistical laws that can be studied and then successfully applied to solving astrophysical problems. In this project, Dr. Alexandre Lazarian (University of Wisconsin - Madison) seeks to advance theoretical understanding of magnetized turbulence in the interstellar medium (ISM) by both studying these laws and comparing theory with observations. These studies will build upon the existing research base and the enabling achievements obtained through Dr. Lazarian's earlier work that focused on the spectra of turbulence and its implications for cosmic rays. The present project is to address the role of small regions within the ISM turbulence in which the physical conditions are far from the average (called "intermittency"), as well as the feedback of cosmic rays to the compressible turbulence. In addition, this research will continue developing, testing, and applying new tools for extracting turbulence spectra from observations of the velocity profiles of spectral lines. As the result of this research, the observational community will have new tools to study turbulence and its anisotropy, as well as the topology of the ISM. The appearance, evolution, and overall properties of a spiral galaxy are strongly influenced by its ISM. In turn, the nature of the ISM and many processes taking place within it (such as star-formation) are determined by the magnetic turbulence that stirs it. Examining magnetic turbulence at a fundamental level is vital to understanding many processes. Turbulence cannot be confidently understood using "brute force" numerical approaches only; the fluid motions simulated by computers differ from astrophysical ones by a huge difference in Reynolds numbers. In addition to the research that will be carried out under this project, Dr. Lazarian will mentor a graduate student as well as supervise REU and undergraduate student research projects. Dr. Lazarian will also carry out outreach activities, such as public lectures, and will make the statistical tools developed as a part of this project publicly available.