Modelling 3D force-free neutron star magnetospheres

ABSTRACT Magnetars exhibit a variety of transient high-energy phenomena in the form bursts, outbursts, and giant flares. It is common belief that these events originate sudden release magnetic energy due to rearrangement twisted field. We present global models 3D force-free (FF) non-linear magnetar magnetosphere. solve FF equations following Grad–Rubin approach compactified spherical domain. Appropriate boundary conditions are imposed at surface star for current distribution Our implementation tested by reproducing various known analytical as well axisymmetric numerical results. then proceed study general with non-axisymmetric distributions, such fields localized twists resemble hotspots star, we examine characteristic quantities energy, helicity, twist. Finally, discuss implications on available budget, temperature, diffusion time-scale, which can be associated observations.