Turbulence in Collisionless Astrophysical Plasmas

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Astrophysical plasmas are rarely observed to be static. Instead they vary strongly in both time and space, a phenomena known as turbulence. Such plasmas are also typically endowed with magnetic fields, just like the Earth and the Sun. An understanding of turbulence in magnetized plasmas (known as MHD turbulence) is thus required to understand a wide variety of astrophysical phenomena, from the solar wind in our solar system (and how the solar wind impacts Earth) to rotating disks of gas falling into black holes (which produce some of the brightest sources of light in the Universe). Our proposed research is aimed at understanding the behavior of MHD turbulence on small scales where the energy is converted into heat. We propose to carry out large-scale numerical calculations of the properties of MHD turbulence on small scales. These calculations will predict observable properties of the turbulence that can be directly compared to measurements in the solar wind, and ultimately to measurements in the laboratory on Earth. The same calculations will predict how plasmas are heated when the energy contained in the turbulence is dissipated -- one of the major unsolved problems in our understanding of turbulence. These results will be compared to measurements in the solar wind; they will also be used to predict the light we see from plasma falling into black holes -- our primary observational window onto black holes in nature. More broadly, the calculations proposed here will advance the state-of-the-art in numerical modeling of turbulence in magnetized plasmas and will have implications for a wide variety of laboratory, space, and astrophysical plasmas.