The study also demonstrates the unique capabilities of the Linac Coherent Light Source (LCLS) X-ray laser at the U.S. Department of Energy (DOE)'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 physics for the first time ever.
The peaks on this chart represent key energy signatures produced in a dense ultra-hot plasma, which for the first time allow detailed measurements of the effects of this plasma environment.
Credit: Image courtesy of Sam Vinko, University of Oxford
Plasma is sometimes referred to as the fourth state of matter – alongside solid, liquid and gas – and in this case it was hundreds of times hotter than the surface of the sun (2 million kelvins or 3.6 million degrees Fahrenheit). These measurements, reported by an international team of researchers and published this week in Physical Review Letters, contradict the prevailing model that scientists have used for a half-century to understand the conditions inside plasmas.
"We don't think this could have been done elsewhere," said Justin Wark, leader of a group at Oxford University that participated in the study. "Having an X-ray laser is key."
The international research team, which made the plasma by targeting super-thin aluminum with X-rays at LCLS, reported its initial results in January. Now, in a second study based on a new analysis of data from the same experiment, the group tackled another question: How are atoms in such a hot, dense plasma affected by their environment?
The researchers were able to pinpoint how much energy it takes to knock electrons from highly charged atoms in a dense plasma. "That's a question no one's been able to test properly before," said Orlando Ciricosta of Oxford University and lead author of the study, which included scientists from three DOE national laboratories.
The LCLS offers a unique test bed for these studies: It provides a very controlled environment for measuring extreme phenomena, a laser beam with finely tuned energies and a way to precisely measure the properties of a plasma at a specific solid density.
The new analysis gives insight into the sorts of plasmas scientists need to create in some experimental approaches to fusion, the process that powers stars, in which the cores of super-condensed atoms combine and release massive amounts of energy. The research may lead to improved modeling for certain aspects of fusion, as it gives detailed information about the process where tightly packed atoms begin to lose their autonomy as the orbits of their associated electrons overlap.
Scientists use complicated algorithms that may include millions of lines of code to simulate the behavior of superheated matter and build better models of how fusion works.
"Even very sophisticated computer codes used to simulate dense plasmas usually employ an old model from 1966 to simulate the effects of the plasma environment," Ciricosta said. "Our work at the LCLS has shown that this widely used model does not fit the data. In an extraordinary twist of fate, it turns out that an even earlier approach from 1963 does a far better job."
Wark said he expects the findings will have "significant impact" in the plasma physics community, as the 1963 model can be easily applied to improve existing simulations in a range of fields. However, the complete physics is still far from clear, and he cautioned that more testing and refinement may be necessary.
"We're not going to claim any current model works under all conditions and works for everything," he said. "We would really like people to go and revisit this problem, to see if they can come up with something even more sophisticated."
Wark's team included researchers from Oxford; SLAC; Lawrence Berkeley National Laboratory; Lawrence Livermore National Laboratory; University of California – Berkeley; the International Atomic Energy Agency in Austria; the Plasma Physics Department at AWE in the United Kingdom; the Institute of Physics ASCR in the Czech Republic; and DESY and the Friedrich-Schiller University in Germany.
The team's research is available for download from Physical Review Letters: http://prl.aps.org/abstract/PRL/v109/i6/e065002
Further analysis is also provided in a "Viewpoint" from the American Physical Society (APS): http://physics.aps.org/articles/v5/88
LCLS is supported by the U.S. Department of Energy's Office of Science. SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science. To learn more, please visit www.slac.stanford.edu.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Squeezing light at the nanoscale
17.06.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences
The Fraunhofer IAF is a »Landmark in the Land of Ideas«
15.06.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.
From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
15.06.2018 | Materials Sciences
15.06.2018 | Ecology, The Environment and Conservation
15.06.2018 | Power and Electrical Engineering