Princeton University Astroplasmas Seminar

Pulsar wind nebulae (PWNe) are energized by the electromagnetic spin-down power of a rapidly rotating neutron star. Their emission is primarily synchrotron, produced by relativistic electrons radiating in a sub-equipartition magnetic field. The processes by which a pulsar wind, which is born in a strongly magnetized state, eventually shares its energy with electrons, have been a long-standing question in the theory of pulsars and their nebulae (sometimes referred to as the sigma-problem). I will discuss how dissipation in PWNe may be understood in terms of a process known as magnetic relaxation, and give an overview in general physics terms of recent advances in this topic. MHD simulations reveal the process is generally turbulent, and that magnetic field structures tend to organize themselves spatially, even when the field lacks net magnetic helicity. I will discuss how this process helps to explain the magnetization level of the Crab's synchrotron nebula.