Scientists Achieve Laser-Generated Star Plasma in Metal Within Trillionths of a Second
Breakthrough research captures copper atoms forming and dissolving highly charged ions in unprecedented detail, advancing laser fusion diagnostics.
Scientists have achieved a remarkable breakthrough in extreme physics by capturing the split-second transformation of metal into star-like plasma using powerful laser pulses. Researchers at Helmholtz-Zentrum Dresden-Rossendorf combined two cutting-edge laser systems to track how copper atoms lose and regain electrons in trillionths of a second, creating highly charged ions in conditions typically found only near neutron stars or during gamma-ray bursts. The achievement provides unprecedented insight into matter behavior under extreme conditions.
The experiment utilized both an X-ray free-electron laser and the high-intensity optical laser ReLaX at the European XFEL facility in Schenefeld, Germany. The team directed intense laser flashes at copper wire samples just one-seventh the thickness of human hair, delivering energy densities reaching 250 trillion megawatts per square centimeter. These ultrashort pulses, lasting only 25 to 30 femtoseconds, allowed researchers to observe ionization processes that unfold within picoseconds.
Dr. Lingen Huang, head of experimentation at HZDR's Division of High-Energy Density, explained that the copper wire instantly vaporized under the extreme conditions, producing plasma with temperatures of several million degrees. As copper atoms lost multiple electrons and became highly ionized, the team used a second laser pulse as a probe to examine the plasma evolution. This pump-probe approach created a sequence of snapshots similar to frames in a movie, tracking the formation and dissolution of Cu²²⁺ ions.
The X-ray pulses were precisely tuned to interact with copper ions that had lost 22 electrons, utilizing resonant absorption at 8.2 kiloelectronvolts to match specific electronic transitions. After absorbing the X-rays, these ions emit distinctive X-ray radiation that researchers could measure over time. This innovative technique allows scientists to track exactly how many highly charged ions are present in the plasma at any given moment during the rapid ionization process.
The research, published in Nature Communications, introduces a promising new method for improving diagnostics in laser fusion research and advancing our understanding of matter under extreme conditions. The ability to create and study such extreme states of matter in laboratory settings could lead to breakthroughs in fusion energy research and provide new tools for investigating cosmic phenomena that occur in some of the universe's most violent environments.
