WoU-MMA Collaborative research: Turbulence and Reconnection in Magnetically-Dominated Astrophysical Plasmas

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In many astrophysical objects -- like bubbles of magnetic fields and high-energy particles powered by rapidly spinning neutron stars called pulsar wind nebulae -- magnetic fields control the overall dynamics of the hot gas of charged particles, the relativistic astrophysical plasma surrounding the object. In such astrophysical objects dissipation of magnetic energy via magnetic reconnection -- a process where magnetic field lines annihilate, releasing their energy to the particles -- may power the observed high-energy electromagnetic and particle emission. A number of recent observations such as the Crab Nebula gamma-ray flares detected by Fermi and AGILE satellites have emphasized the critical role of magnetic reconnection for the acceleration of the emitting particles in astrophysical high-energy sources. This work will include projects for undergraduate students, and the results will be disseminated to high-school students through dedicated workshops. A new program, "Astro-soup," will be implemented, where serving food to homeless people in New York City will be accompanied by discussion on astrophysical topics of relevance for this work. The overall goal of this research is to explain the puzzling phenomenology of non-thermal emission in the Crab Nebula, the prototype of pulsar wind nebulae and the most famous source in high-energy astrophysics. Its flaring and quiescent signatures will be modeled, from radio to high-energy gamma-rays, in a single physically-grounded scenario based on relativistic magnetic reconnection. Every stage of the research will combine analytical approaches with large-scale first-principles particle-in-cell simulations. The reconnection model of astrophysical high-energy sources will be placed on solid footing by studying from first principles how reconnection layers are self-consistently generated by large-scale flows occurring in the Crab Nebula and how the interplay of reconnection and fluid motions can naturally lead to efficient particle acceleration. The results will also be relevant for other flaring sources, like jets from supermassive black holes, where gamma-ray flares have recently been detected together with neutrino counterparts, thus addressing the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" Big Idea.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.