报告摘要：
Many astrophysical plasmas are dilute enough that the mean free path of
particles is long compared to their gyro-radius, but still small compared to
macroscopic length scales in the system. In this regime, the simplest
description of the plasma dynamics is given by the equations of MHD,
supplemented with anisotropic transport coefficients for heat (conduction)
and momentum (viscosity). Remarkably, this produces qualitative changes
in the dynamics. For example, in this regime the convective stability
criterion depends only on the temperature (rather than the entropy)
gradient. The physics of this, and two other MHD instabilities, will
be described, with application to the X-ray emitting plasma in clusters
of galaxies, and hot accretion flows onto compact objects.

报告人介绍:
James Stone is a Professor in the Department of Astrophysical Sciences
at Princeton University (with a joint appointment in the Program in
Applied and Computational Mathematics), and Associate Director of
the Princeton Institute for Computational Science and Engineering.
He received a PhD in astronomy from the University of Illinois in 1990,
and was a postdoctoral research associate at the University of Illinois
for two years, before joining the faculty at the University of Maryland
in 1992. In 2002 he was elected to the Professorship of Mathematical
Physics at Cambridge University, and moved to Princeton in 2003.