TAP Colloquium - Dr. Matthew W. Kunz
Waves, Turbulence, Heating, and Transport in Magnetized, Weakly Collisional Astrophysical Plasmas
Dr. Matthew W. Kunz
The transport of energy and momentum and the heating of plasma particles by waves and turbulence are key ingredients in many problems at the frontiers of heliospheric and astrophysics research. This includes the heating and acceleration of the solar wind; the observational appearance of black-hole accretion flows on event-horizon scales; and the properties of the hot, diffuse plasmas that fill dark-matter halos. All of these plasmas are magnetized and weakly collisional, with plasma beta parameters of order unity or even much larger. In this regime, deviations from local thermodynamic equilibrium (i.e., pressure anisotropies) and the kinetic instabilities they excite can dramatically change the material properties of such plasmas and thereby influence the macroscopic evolution of their host systems. Departing from the astronomical tradition of abstracting these physics into crude, sub-grid prescriptions, this talk outlines an ongoing programme of kinetic calculations aimed at elucidating from first principles the physics of waves, turbulence, heating, and transport in magnetized, weakly collisional astrophysical plasmas. Contact will be made between this detailed plasma physics and the broader science questions concerning low-luminosity accretion flows and the intracluster medium of galaxy clusters.