Applied and Fundamental Physics (P-2) is a diverse group of experimental physicists, engineers, technicians, and students engaged in a range of fundamental and applied research in nuclear physics beyond the Standard Model, neutrinos, dark matter, weapons physics, plasma physics, and fluid dynamics. We support a diverse program that includes scientists of many nationalities, participation in experiments worldwide, sponsorship of workshops and conferences, and classified experiments and analysis.

User facilities

P-2 operates two user facilities supported by the Los Alamos Neutron Science Center (LANSCE) accelerator, making important scientific contributions to national security, academia, and industry by exploiting the unique characteristics of intense beams of unmoderated pulsed neutrons at the Weapons Neutron Research Facility, moderated pulsed neutrons at the Lujan Center, and protons at Target 2. Our operations team brings unique expertise for operating and developing the Weapons Neutron Research and Lujan Center user facilities. Team members have successfully implemented a high-quality operations plan at Lujan Center, with recognized top-tier conduct of operations. Other team members are experts in operating and maintaining the neutron-producing spallation target at WNR and Lujan Center, as well as supporting neutron flight path experiments and ancillary instruments. We host an experimental program focusing on measuring neutron-induced single event upset for avionics and the microelectronic industry.

Physics of dynamic materials

Group members perform subcritical experiments to investigate the physics of dynamic materials. The work on subcritical experiments fields novel and unique diagnostics to measure and understand the shocked behavior of plutonium at the Nevada National Security Site in support of science-based stockpile stewardship. The group’s dynamic materials work also explores the physics of materials under extreme conditions. Sophisticated measurements that this team specializes in include neutron cross sections, time-resolved pyrometry, x-ray radiography, high-speed visible imaging, holography, and momentum diagnostics. On the defense science front, the team supports a variety of weapons-relevant efforts including neutron-diagnosed subcritical experiments, developing advance optical diagnostics, and laser-based ranging diagnostics.

Fluid dynamics

P-2 applies high-resolution diagnostics to study fluid dynamics problems in extreme environments, such as shock-driven mixing and variable-density decaying turbulence. The data are then used to improve our understanding of these complex systems and help to validate the hydrodynamic mix models in our multi-physics simulations. Applications range from weapon design to astrophysics and inertial confinement fusion.

Nuclear weapons data analysis

We have expertise in reanalyzing and archiving neutron data from past nuclear weapons tests, in addition to designing and fielding modern diagnostics like energy release and Mie scattering. P-2 group members are responsible for understanding, archiving, and reanalyzing as needed a majority of the diagnostics that were used in underground testing, including gamma- and neutron-based diagnostics. Our staff members contribute to Laboratory programs in stockpile stewardship by participating in nuclear and materials science—from fundamental understanding of nuclear structure and reactions to the characterization of materials under extreme environments— which is intimately connected with Los Alamos National Laboratory’s mission to solve national security challenges through scientific and operational excellence.