APS News

APS Plasma, Nuclear, and Laser Divisions Hold Fall Meetings

Division of Plasma Physics (DPP)
Physicists from across the country gathered for the largest annual plasma physics meeting in the nation. The 52nd annual Division of Plasma Physics Meeting was held at the Hyatt Regency Chicago in downtown Chicago from November 8 through 12. The meeting highlighted the latest discoveries and breakthroughs in all plasma- related fields.

Some of the most exciting work in the field is focused on understanding and mitigating focused bands of heat escaping from magnetic containment rings inside fusion reactors. These bands of extreme heat, called footprints, jet out from a fusion reaction along magnetic field lines otherwise used to contain the heat, and have so far hampered progress towards developing effective methods to fully contain the reaction. Tuesday afternoon’s session focused on the continuing problems of containment by developing a deeper understanding of the counterintuitive physics governing the size of the footprints and other ways to eliminate impurities and energy oscillations in the fusion reaction.

The largest fusion reactor in the solar system, the Sun, is getting some attention of its own. James Chen of the Naval Research Lab took a close look at the Sun’s coronal mass ejections, prominences of magnetized plasma that stretch millions of miles out from the solar surface. Chen’s new model rejects the existing understanding of how these ejections work, instead finding that a magnetic “flux rope” is the cause of the size and strength of these ejections, a concept originally developed to understand containment in Tokomak reactors. Clifford Surko from the University of California San Diego discussed how plasma science carries over into the study and isolation of anti-matter as well. Greg Hebner from the Sandia National Laboratories delivered an overview of how plasma physics has been integral to developing new products and working towards energy independence.
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Division of Nuclear Physics (DNP)
The Division of Nuclear Physics held its annual meeting from November 2 through 6 at the Santa Fe Convention Center in Santa Fe, New Mexico. Emiko Hiyama of RIKEN explained recent advances in understanding baryon-baryon interactions, and Tim Gorringe from the University of Kentucky released results from his experiments with the MuLan Collaboration that have measured the lifetime of the positive muon, accurate to a single part per million.

Similarly, Anatolii Serebrov from the Russian Academy of Sciences presented research that the lifetime of a neutron is roughly 1.1 seconds longer than previously thought, at roughly 879.9 seconds, with an uncertainty of .9 seconds. The important intersection of neutrino nuclear physics and cosmology was explored in depth by George Fuller, University of California, San Diego. The importance of nuclear physics to astrophysics and astronomy was a major feature of the meeting.

Hendrik Schatz from Michigan State University gave an outline of how understanding the masses of nuclei are essential to understanding astrophysical events. Christian Ott of Caltech presented the first 3-D computer model tracking the core of a massive star as it undergoes gravitational collapse, and forms a proto-neutron star phase which subsequently collapses forming a black hole.
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Division of Laser Science (DLS) 
The joint OSA/APS conference Frontiers in Optics/Division of Laser Science was held October  24 through 28 at the Rochester Riverside Convention Center in Rochester, New York. At the meeting David DeMille of Yale and his team announced the coldest whole molecules ever created. Using three lasers to trap molecules of strontium and fluorine, DeMille was able to chill the molecules to 300 micro-Kelvins along one axis.

Michael Romalis and his team at Princeton reported on their test confirming Lorentz invariance with accuracy improved by a factor of thirty. A new high-tech technique for looking at tooth decay was described by a team of researchers from the University of Rochester. They used Raman spectroscopy to distinguish the plaque strain Streptococcus sanguis, which fights decay, from the cavity-causing mutans strain.

Friday morning began with a free tour of the Omega Laser Facility at the University of Rochester’s Laboratory for Laser Energetics. Monday’s plenary sessions featured Steven Block from Stanford University describing his work merging physics and biology to create new tools and applications such as using optical tweezers to trap biological macromolecules for study.

Also at the plenary, Alain Aspect from the Laboratoire Charles Fabry de l’Institut d’Optique in France recalled how fifty years ago an experiment developed by R. Hanbury Brown and R. Q. Twiss to measure the angular diameter of stars ultimately led to the development of modern quantum optics. 
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Editor: Alan Chodos