In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as it transitions into a superhot, highly compressed concoction known as “warm dense matter.”
SLAC National Accelerator Laboratory
This illustration shows a cutaway view of Jupiter, which is believed to contain "warm dense matter" at its core. A study at SLAC's Linac Coherent Light Source X-ray laser has provided the most detailed measurements yet of a material's temperature and compression as it transitions into this exotic state of matter.
Warm dense matter is the stuff believed to be at the cores of giant gas planets in our solar system and some of the newly observed “exoplanets” that orbit distant suns, which can be many times more massive than Jupiter. Their otherworldly properties, which stretch our understanding of planetary formation, have excited new interest in studies of this exotic state of matter.
The results of the SLAC study, published March 23 in Nature Photonics, could also lead to a greater understanding of how to produce and control nuclear fusion, which scientists hope to harness as a new source of energy.
“The heating and compression of warm dense matter has never been measured before in a laboratory with such precise timing,” says Siegfried Glenzer, a distinguished staff scientist who is part of the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC. “We have shown the detailed steps of how a solid hit by powerful lasers becomes a compressed solid and a dense plasma at the same time. This is a step on the path toward creating fusion in the lab.”
A team led by Glenzer used laser light to compress ultrathin aluminum foil samples to a pressure more than 4,500 times higher than the deepest ocean depths and superheat it to 20,000 kelvins – about four times hotter than the surface of the sun. SLAC’s Linac Coherent Light Source X-ray laser, a DOE Office of Science User Facility, then precisely measured the foil’s properties as it transformed into warm dense matter and then into a plasma – a very hot gas of electrons and supercharged atoms.
Warm dense matter remains largely mysterious because it is difficult to create and study in a laboratory, can exhibit properties of several types of matter and occupies a middle ground between solid and plasma. Our own sun is an example of a self-sustaining plasma, and plasmas have also been harnessed in some TV displays.
While warm dense matter is believed to exist in a stable state at the heart of giant planets, in a laboratory it lasts just billionths of a second. Scientists have relied largely on computer simulations, driven by scientific theories, to help explain how a solid, when shocked with powerful lasers, transforms into a plasma.
LCLS, with its complement of high-power lasers, is uniquely suited to creating and studying matter at the extremes. Its ultrabright X-ray pulses are measured in femtoseconds, or quadrillionths of a second, so it works like an ultra-high-speed X-ray camera to illuminate and record the properties of the most fleeting phenomena in atomic-scale detail.
In this experiment, researchers used a high-power optical laser at LCLS's Matter in Extreme Conditions experimental station to fire separate beams of green laser light simultaneously at both sides of coated, ultrathin aluminum foil samples, each just half the width of an average human hair. The lasers produced shock waves in the material that converged to create extreme temperatures and pressures.
Researchers struck the samples with X-rays just nanoseconds later, and varied the arrival time of the X-rays to essentially make a series of snapshots of warm dense matter formation. The team used a technique known as small angle X-ray scattering to measure the internal structure of the material, capturing its brief transition into the warm dense state.
“This early work with aluminum is a first stepping stone toward other problems we really need to solve,” Glenzer said, such as how hydrogen behaves under similar conditions. Hydrogen, which makes up about 75 percent of the visible mass of the universe, plays a central role in fusion, the process that powers stars. A better understanding of how hydrogen transitions into warm dense matter could help settle debates over conflicting theories on this transition and help unlock the secrets of fusion energy.
“I think LCLS can help to resolve the hydrogen ‘controversy,’ in upcoming experiments,” Glenzer said.
Participants in the research included scientists at SLAC, University of California Berkeley, Lawrence Livermore National Laboratory and General Atomics; QuantumWise A/S in Denmark; AWE plc, University of Warwick and University of Oxford in the U.K.; and the Max Planck Institute for the Physics of Complex Systems, Institute for Optics and Quantum Electronics, Friedrich-Schiller-University and GSI Helmholtz Center for Heavy Ion Research in Germany.
The work was supported by the DOE Office of Science, Fusion Energy Science; the DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division; Lawrence Livermore National Laboratory; a Laboratory Directed Research and Development grant; and the Peter-Paul-Ewald Fellowship of the VolkswagenStiftung.
SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, Calif., SLAC is operated by Stanford University for the U.S. Department of Energy's Office of Science. For more information, please visit slac.stanford.edu.
SLAC National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The 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.
External Communications Manager
Andrew Gordon | newswise
First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science
Nuclear physicists leap into quantum computing with first simulations of atomic nucleus
24.05.2018 | DOE/Oak Ridge National Laboratory
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Ecology, The Environment and Conservation
24.05.2018 | Medical Engineering
24.05.2018 | Physics and Astronomy