Wed, 04/03/2019 - 3:00pm to 4:00pm
Space Science Seminar
Dr. Vladimir Zhdankin from Princeton University
Particle energization in relativistic plasma turbulence
Abstract: Turbulence is ubiquitous in high-energy astrophysical systems such as pulsar wind nebulae, black-hole accretion flows, and jets. The plasmas in such systems are often collisionless and relativistic. I will describe recent numerical and theoretical progress on understanding turbulence in relativistic collisionless plasmas. I will present results from particle-in-cell simulations, which provide a first-principles approach to studying the turbulence statistics in great detail. One main outcome is the confirmation that turbulence can be an efficient and viable astrophysical particle accelerator, producing nonthermal energy distributions with extended power laws, supporting theoretical ideas that have been debated for decades. I will also discuss intriguing results on electron-ion energy partition, showing that the dissipation of turbulence naturally produces a two-temperature plasma (with ions much hotter than electrons), as required by models of radiatively inefficient accretion flows. Finally, I will describe recent results on the effect of inverse Compton radiation, which thermalizes the particles and allows intermittent beaming.