Physics Colloquium with Yajie Yuan on Particle Accelerators
Black holes and neutron stars produce the most spectacular relativistic outflows. These are usually prolific emitters of high energy radiation; they may also produce high energy neutrinos and ultra-high energy cosmic rays. How the energy from the central engine goes into particle energization and radiation has been a long standing puzzle. Right now with the unprecedented advantage in multiwavelength/multimessenger observations, and rapid progress in high-performance, large-scale simulations, we are getting closer to the physical answer. Using first-principles simulations, my recent works have shown that dissipation of the large electromagnetic energy in these outflows may power gamma-ray flares from relativistic jets, X-ray emission from accretion disk coronae, and fast radio bursts from magnetars. In this talk, I will discuss some of this progress, and promising future directions.