Speaker
Description
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 (LTE) 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. This talk outlines an ongoing programme of hybrid-kinetic and fluid-kinetic calculations aimed at elucidating from first principles the multi-scale physics of magnetized, weakly collisional, high-beta astrophysical plasmas. Interrupting Alfvén waves, self-sustaining sound waves, microphysically modified magnetosonic modes, mirror-infested current sheets, and magneto-immutable turbulence will feature in a discussion of how self-generated pressure anisotropies fundamentally alter waves, turbulence, and heating in dilute astrophysical plasmas.
