February 13, 2026 by Chris Patrick, SLAC National Accelerator Laboratory
Collected at: https://phys.org/news/2026-02-ray-platform-images-plasma-instability.html
Harnessing the power of the sun holds the promise of providing future societies with energy abundance. To make this a reality, fusion researchers need to address many technological challenges. For example, fusion reactions occur within a superheated state of matter, called plasma, which can form unstable structures that reduce the efficiency of those reactions.
Characterizing different instabilities could help researchers prevent or make use of them. One particular instability, known as current filamentation, is also relevant to understanding astrophysical phenomena.
Now, for the first time, a team led by researchers at the U.S. Department of Energy’s SLAC National Accelerator Laboratory imaged how the current filamentation instability evolves in real time in high-density plasma.
Their work, reported in Nature Communications, demonstrates a new way to study instabilities in plasmas using SLAC’s Linac Coherent Light Source (LCLS) X-ray laser.
“This is the most detailed description of this instability yet,” said Christopher Schoenwaelder, project scientist at SLAC and first author of the paper. “We actually image the evolution of the instability and then combine that with state-of-the-art simulations to try to make constraints on existing theoretical models of it.”
Co-author Siegfried Glenzer, High Energy Density Division director and professor of photon science at SLAC, said, “Our understanding of instabilities—when they grow, how they grow—is important to making fusion work.”
Left to right: X-ray images show how filament structures known as current filamentation instability evolve in plasma over time. Credit: C. Schoenwaelder et al., Nature Communications, 9 January 2026
Energetic X-rays yield unprecedented resolution
In the current filamentation instability, a laser accelerates electrons in a plasma to very high energies, producing a current of hot electrons. This current interacts with a return current of cold electrons streaming in the opposite direction, which gives rise to the filament-shaped instability.
While this instability has been imaged in low-density plasmas, it’s more challenging to study in high-density plasmas, which conventional imaging methods cannot penetrate. However, studying denser plasmas is important for understanding inertial fusion plasmas, which have very high densities.
The high-intensity X-rays from the LCLS carry enough energy to pass through a high-density plasma and produce an image of the instability forming within, which the team induced with a powerful laser at the Matter in Extreme Conditions (MEC) instrument.
The resultant images showed the formation of the micrometer-scale filamentary structures over a tiny fraction of a second, providing unprecedented spatial and temporal resolution of this instability.
“Every 500 femtoseconds [quadrillionths of a second], we took snapshots to get a true image of what was happening at that moment in time, showing details like never before,” Glenzer said.
Schematic of a novel setup at the Matter in Extreme Conditions experiment at SLAC’s LCLS X-ray laser. It allowed researchers to produce and image a specific instability in extremely hot, dense plasma. A powerful, high-intensity laser (at left, red beam) is focused on hair-thin wire targets to create the dense plasma conditions. LCLS’s X-rays (blue beam) are then used like a microscope to take snapshots of how the plasma and instabilities within it evolve in real time. By adjusting the timing between the laser and X-ray pulses, the team can capture a sequence of images that reveals how the instability develops over extremely short time scales (at right). Credit: C. Schoenwaelder et al., Nature Communications, 9 January 2026
A new way to study plasma instabilities
Schoenwaelder and Maxence Gauthier, associate staff scientist at SLAC, spearheaded the experimental aspects of this work. Alexis Marret, research associate at SLAC, and Frederico Fiúza, a professor of physics at the University of Lisbon, Portugal, and visiting professor of photon science at SLAC, focused on the simulation side. By comparing cutting-edge simulations of the experiment with the data and theory, they identified mechanisms that shape the evolution of this instability.
The analysis also showed that, during the experiment, the instability produced a 1,000-Tesla magnetic field, which is about 100,000 times stronger than that of a typical refrigerator magnet. In plasmas in astrophysical phenomena, such as exploding stars, this strong magnetic field amplification is thought to enable the acceleration of high-energy particles known as cosmic rays.
Eventually, a better understanding of this instability could allow scientists to use plasma experiments in the lab to learn about events happening light-years away.
The platform developed in this work could also be extended to study other types of plasma instabilities, including those that take energy away from fusion reactions.
Publication details
Christopher Schoenwaelder et al, Time-resolved X-ray imaging of the current filamentation instability in solid-density plasmas, Nature Communications (2026). DOI: 10.1038/s41467-025-67160-2
Journal information: Nature Communications
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