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Magnetic reconnection—a fundamental plasma physics process, where magnetic field lines of opposite polarity annihilate—is invoked in astrophysical plasmas as a powerful mechanism of nonthermal particle acceleration, able to explain fast-evolving, bright high-energy flares. Near black holes and neutron stars, reconnection occurs in the relativistic regime, in which the mean magnetic energy per particle exceeds the rest mass energy. This review reports recent advances in our understanding of the kinetic physics of relativistic reconnection:▪Kinetic simulations have elucidated the physics of plasma heating and nonthermal particle acceleration in relativistic reconnection (RR).▪The physics of radiative RR, with its self-consistent interplay between photons and reconnection-accelerated particles—a peculiarity of luminous, high-energy astrophysical sources—is the new frontier of research.▪RR plays a key role in global models of high-energy sources, in terms of both global-scale layers as well as reconnection sites generated as a by-product of local magnetohydrodynamic instabilities. We summarize themes of active investigation and future directions, emphasizing the role of upcoming observational capabilities, laboratory experiments, and new computational tools.
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Fundamental Neutron Physics at Spallation Sources
Low-energy neutrons have been a useful probe in fundamental physics studies for more than 70 years. With advances in accelerator technology, many new sources are spallation based. These new, high-flux facilities are becoming the sites for many next-generation fundamental neutron physics experiments. In this review, we present an overview of the sources and the current and upcoming fundamental neutron physics programs.
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- Award ID(s):
- 1849213
- PAR ID:
- 10410813
- Date Published:
- Journal Name:
- Annual Review of Nuclear and Particle Science
- Volume:
- 72
- Issue:
- 1
- ISSN:
- 0163-8998
- Page Range / eLocation ID:
- 151 to 176
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1146/annurev-nucl-121521-051029
