Sackler Lecture: The Microphysics and Macrophysics of Cosmic Rays

Ellen Zweibel (University of Wisconsin-Madison)

April 13, 2015

–

Abstract: Cosmic rays represent only a billionth of interstellar particles by number, but carry as much energy as the thermal gas. Due to their high energies they are virtually collisionless, and exchange energy and momentum with the background primarily through tiny scale fluctuations in the ambient magnetic field. I will discuss the interactions with these fluctuations and their consequences, including the driving of galactic outflows, the heating of interstellar and intracluster gas, and the self-regulation of the cosmic ray acceleration process itself. Recent gamma-ray observations of the Milky Way and other galaxies are fleshing out and modifying this picture.