Description:

CIERA Fall Interdisciplinary Colloquium 2014

The Role of Computation in Astrophysical Plasma Dynamics

           Jim Stone (Princeton University)

Most of the visible matter in the Universe is a plasma -- that is a dilute gas of electrons, ions, and neutral particles. The time-dependent dynamics of astrophysical plasmas are described by a system of nonlinear coupled partial differential equations. Often additional systems of equations that describe more physics, such as self-gravity and radiation transport, must be coupled to the underlying equations of motion. Over the past few decades, computational methods have emerged as the most powerful approach for solving such complex problems. In this talk, I will begin by introducing some fundamental challenges in theoretical astrophysics that require detailed modeling of plasma dynamics, such as star formation, and understanding how compact objects such as black holes accrete plasma from interstellar space. I will then describe a variety of numerical algorithms that have been developed to model astrophysical plasma dynamics, including new methods for calculating time-dependent radiation transport in relativistic flows. Efficient implementation of these methods on modern parallel high-performance computing systems is crucial, and will be discussed. Finally, I will describe some of the many new insights that have come from applying computational methods to studies of a variety of problems, from black hole accretion flows to star formation in the turbulent interstellar medium.