6 July 2015

IAEA’s contribution to Plasma Physics Research is recognized with high honour by the American Physical Society

Map from the WISER web application on NUCLEUS

The peaks on this chart represent key energy signatures produced in a dense ultrahot plasma, which for the first time allow detailed measurements of the effects of this plasma environment. (Image Courtesy of Sam Vinko, University of Oxford)

The American Physical Society (APS) has recently selected Dr Hyun Kyung Chung, atomic physicist in the IAEA’s Division of Physical and Chemical Sciences, as one of the recipients of the 2015 John Dawson Award for Excellence in Plasma Physics Research. It was thanks to her unique contribution and expertise in atoms physics modelling that this recognition was able to be achieved and granted to her.

This Award was established to recognize outstanding achievement in plasma physics research. The 2015 Award recognizes Dr Chung and her collaborators’ achievements “For creative and novel use of the hard x-ray free electron laser to isochorically create high density plasmas and accurately measure the ionization potential depression, and for new theory that addresses discrepancies with long standing models and provides stimulus for continued developments.”

Dr Chung has long been associated with research using the Linac Coherent Light Source (LCLS) X-ray laser at Stanford, both as a member of the LCLS proposal review panel and as a member of an international team led by Oxford University participating in the LCLS experiments. She will share this award with her co-workers Roger Falcone, University of California – Berkeley, Phillip Heimann, Richard W Lee, Bob Nagler from SLAC National Accelerator Laboratory, Orlando Ciricosta, Sam Vinko and Justin Wark from Oxford University. Their work has led to publications in Nature, Physical Review Letters (PRL) and other respected journals starting in 2012 and including a Nature communication and a PRL in 2015. One key concept in this work is that of ionization potential depression; a collective effect by which the ionization potential of an ion in dense plasma is lowered relative to that of the free ion. The effect is very difficult to calculate from first principles as it involves electronic structure for very many electronic excited states in a disordered medium. Dr Chung’s contribution, the understanding of atomic processes of plasmas, was highly important in the published research.

The studies undertaken by the international team demonstrate the unique capabilities of the LCLS X-ray laser at the U.S. Department of Energy’s SLAC National Accelerator Laboratory. While researchers have created extremely hot and dense plasmas before, LCLS allows them to measure the detailed properties of these states and test a fundamental class of plasma processes for the first time. These controlled studies of extremely hot, dense matter have overthrown the widely accepted 50-year-old model used to explain how ions influence each other’s properties in dense plasma. The results of Dr Chung and her collaborators should benefit a wide range of fields, from research aimed at tapping nuclear fusion as an energy source to understanding the inner workings of stars.

Dr Chung will attend the annual meeting of the Division of Plasma Physics to be held in Savannah, GA, November 16-20, 2015 for the bestowal of the Award. The announcement of her selection for the Award and the citation will also be published in the next March edition of the APS News.