Speaker
Description
Magnetars are among the most extreme magnetized environments in the universe, and modeling their magnetohydrodynamic (MHD) evolution is central to understanding how their fields are generated, structured, and sustained. While these objects are observed through energetic transients such as Soft Gamma Repeaters and Anomalous X-ray Pulsars, the configuration and longevity of their internal magnetic architecture remain poorly constrained. In this talk, I will present results from three-dimensional general relativistic MHD simulations of magnetic field evolution in these systems. Our numerical survey isolates how rotation rate and initial magnetic field strength—individually and in combination—drive magnetic instabilities and shape the resulting field topology. By varying these parameters systematically, we disentangle their respective roles in setting the long-term stability and structure of magnetar fields. We identify two distinct evolutionary regimes governed by the competition between rotation and field strength: rapid rotation enables shear-driven growth of the azimuthal field, whereas strongly magnetized configurations develop poloidal instabilities that drive rapid field dissipation. These results bear on the broader question of magnetic field amplification and saturation in compact objects, connecting to MHD processes also at play in core-collapse supernovae and neutron star mergers.