Speakers
Description
The internal magnetic field configuration of neutron stars remains a key open problem in relativistic astrophysics, with significant implications for their evolution and electromagnetic and gravitational-wave emission. In our work, we investigated the stability of axisymmetric magnetic field configurations in a $n=1$ polytropic neutron star by combining the study of Configurational Entropy (CE), i.e., a measure of informational complexity in Fourier space, with magnetohydrodynamic simulations performed using the PLUTO code. The equilibrium solutions of our model of the magnetic field are described by a discrete set of eigenvalues $\lambda$, which regulate the relative strength and complexity of the toroidal and poloidal components. We found that the CE of the magnetic energy density exhibits a clear maximum at the second eigenvalue, indicating a transition between stable and unstable configurations. Numerical simulations support this interpretation: the lowest eigenvalue configuration, corresponding to minimum energy at fixed magnetic helicity, remains stable over multiple Alfvén timescales, whereas higher-$\lambda$ configurations undergo significant magnetic rearrangement and energy dissipation. These results suggest that configurational entropy provides an effective diagnostic tool for the assessment of stability in magnetised compact objects and place quantitative constraints on the allowed complexity of their internal magnetic field structure.