Unraveling Neutron Star Transients: Insights from High-Resolution GRMHD Simulations

Neutron stars (NSs) represent exceptional astrophysical laboratories, exhibiting extreme magnetic fields and dynamic magnetospheres that drive diverse high-energy transients, including flares, oscillations, and mode switching. These phenomena provide unparalleled opportunities to investigate plasma physics under some of the most extreme conditions in the universe. Leveraging high-resolution 3D general relativistic magnetohydrodynamics (GRMHD) simulations implemented with the H-AMR code, I analyze the intricate interactions among magnetic fields, rotational dynamics, and plasma environments. In this talk, I will discuss advanced simulations that elucidate the physical mechanisms underlying these transients, with a focus on both isolated and accreting NS systems. For isolated NSs, I examine the processes that give rise to magnetar flares and their observable signatures across the electromagnetic spectrum, particularly in X-ray and gamma-ray wavelengths. For accreting NSs, I explore the complex dynamics at the disk-magnetosphere interface, including phenomena such as accretion flows, disk tearing, and the generation of quasi-periodic oscillations (QPOs).