Plasma Dynamics in Radiation-Rich Magnetar Magnetospheres: Implications for Multi-Wavelength Emission

About This Grant

Magnetars are young, highly magnetized neutron stars. Interactions between the strong magnetic fields, the dense neutron star material, and the hot plasma surrounding the magnetar can drive intense bursts of X-ray and radio emission and sustain the production of high-energy X rays. A research group at Dartmouth College will develop quantitative, self-consistent models of plasma flows around magnetars, enabling direct comparisons to observations. Understanding emission from these objects will provide a unique probe into extreme physics and provide insight into some of the universe’s most energetic processes. The research program also includes a comprehensive educational and outreach program to foster STEM education and public engagement in computational high-energy astrophysics. This project combines novel theoretical concepts about quantum electrodynamics (QED) reactions in super-Schwinger magnetic fields with innovative numerical tools to provide unprecedented insights into the plasma dynamics of magnetar magnetospheres. Advanced particle-in-cell (PIC) simulations using the ENTITY code will synthesize angularly dependent spectra of energetic photons escaping the magnetosphere, directly comparable to observed magnetar X-ray activity. The project has four main goals: (1) build an efficient infrastructure for modeling radiation-rich magnetar magnetospheres, (2) investigate different strong-field QED reactions capable of sustaining the magnetar circuit, including resonant inverse Compton scattering (RICS), (3) compare simulation results directly to observational data to infer the microphysics behind magnetar emission and its impact on the magnetar atmosphere’s thermal structure, and (4) enhance next-generation tools for modeling compact object magnetospheres. The proposal includes plans for a fall school program, public outreach activities, and educational animations explaining magnetar phenomena. Collectively, these activities will contribute to enhancing scientific literacy, promoting careers in STEM, and increasing the broad societal impact of astrophysics research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.