@article{9238,
  author = {B. Tripathi and A. E. Fraser and P. W. Terry and E. G. Zweibel and M. J. Pueschel and R. Fan},
  title = {Large-scale dynamos driven by shear-flow-induced jets},
  abstract = {At every scale they occupy, magnetic fields affect various phenomena, including star formation, cosmic-ray transport, charged-particle acceleration, space weather, transport in planetary atmospheres and laboratory plasmas. These fields are often generated and sustained by turbulent flows in a process called the dynamo. In 1955, E.N. Parker parameterized the effects of small-scale turbulence to propose a mean-field dynamo theory [1]. The widely used theory reproduces observed large-scale fields but suffers from difficulty in tuning parameters as they are not justified from first principles: studies of turbulent flows show tangled magnetic fields, which are folded and fragmented into small-scale structures owing to shear-flow straining [2,3]. Here, considering a shear flow that is unstable and driven, we develop analytic theory and perform three-dimensional, advanced computer simulations of turbulence with up to 4,096 × 4,096 × 8,192 grid points, showing ab initio generation of quasi-periodic, large-scale magnetic fields. The generation occurs via the mean-vorticity effect—an additional mean-field dynamo process postulated [4] in 1990. Crucial to this dynamo is the prior generation of large-scale three-dimensional jets, robustly produced as topologically protected and exact nonlinear solutions of the magnetohydrodynamic equations. The jet-driven dynamo applies to shear-driven laboratory and astrophysical systems. These include binary neutron star mergers [5,6], where the reported dynamo probably operates on microsecond timescales to produce in milliseconds some of the strongest magnetic fields in the Universe [7], providing signals for multi-messenger astronomy [8].},
  year = {2026},
  journal = {Nature},
  volume = {649},
  pages = {848-852},
  doi = {10.1038/s41586-025-09912-0},
  language = {eng},
}