author={Riccardo Ciolfi and Samuel K. Lander and Gian Mario Manca and Luciano Rezzolla},
  journal={The Astrophysical Journal Letters},
The problem of the stability of magnetic fields in stars has a long history and has been investigated in detail in perturbation theory. Here, we consider the nonlinear evolution of a nonrotating neutron star with a purely poloidal magnetic field, in general relativity. We find that an instability develops in the region of the closed magnetic field lines and over an Alfvén timescale, as predicted by perturbation theory. After the initial unstable growth, our evolutions show that a toroidal… 

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