ABSTRACT

This project will study the physics of atmospheres of neutron stars and black holes with very strong magnetic fields. Observational discovery of compact stars in our galaxy that are extraordinarily strong magnets, called magnetars, brings modern science into an uncharted territory of enormous magnetic fields. This is where quantum mechanics, rather than everyday physics, describes objects as massive as our Sun. At the same time, detection of gravitational wave signals from merging black holes and neutron stars opened a new observational domain for studies of objects governed by extremely strong gravity. Magnetars, neutron stars and black holes are astrophysical multi-messenger laboratories for studies of the interplay of electromagnetic, quantum, and gravitational effects. The primary goal of this project is to better understand such systems by developing a comprehensive description of collective non-linear behavior of matter in super-strong magnetic and gravitational fields; by doing so, it will also directly contribute to the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" Big Idea. This collaborative project will serve to train graduate students and to promote diversity by recruiting students from underrepresented minority groups.

Magnetars -- neutron stars with magnetic fields exceeding the critical Schwinger field, merging neutron star and black hole binaries, and collapsing neutron stars are the primary astronomical sources where quantum electrodynamic (QED) and general relativistic (GR) effects strongly affect the properties and behavior of plasma. This project aims to understand the dynamics of collisionless pair plasmas in such environments. Moreover, recent advances in laser technology allow state-of-the-art high-intensity laser systems to approach regimes relevant for studies of plasma under such extreme, super-critical field conditions. Upcoming laser-plasma experiments and multi-messenger astronomy observations will allow one to probe into extreme plasma and astrophysical phenomena that were previously inaccessible; and this project will create theoretical and numerical modeling foundations for interpreting results of such laboratory experiments and astronomical observations. The specific questions to be addressed are: (i) What are the plasma properties, collective plasma modes and instabilities in a supercritical magnetic field? (ii) How do GR and QED effects change the dynamics of magnetic reconnection? (iii) How does a black hole formed in the collapse of a magnetized neutron star dissipate its magnetic field? (iv) How do rotating black holes produce electron-positron plasmas? These questions will be answered using a combination of analytical and numerical approaches.

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.

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