Beamstop-free X-ray scattering captures multiscale plasma dynamics
A new X-ray scattering technique has simultaneously measured plasma structures from 10 nanometers to 500 nanometers with sub-picosecond resolution, offering a major advance for high-energy-density plasma diagnostics.
Scientists have captured plasma nanostructures from the nanoscale to the submicrometer scale in a single X-ray pulse. The study, published in Communications Physics on October 24, 2026, demonstrated simultaneous measurement of plasma structures from 10 nm to 500 nm using a single X-ray pulse and camera, achieving sub-picosecond temporal resolution.
Researchers at the National Institutes of Natural Sciences used the SACLA X-ray free-electron laser in Hyogo Prefecture alongside a high-intensity femtosecond pulsed laser. They targeted a silicon microscale rod assembly made of submicrometer cylinders arranged in a regular pattern. The experiments revealed the dynamics of plasma structural collapse and rarefaction, measuring key parameters like rarefaction velocity and electron temperature on picosecond timescales.
Enhanced measurement range through beamstop-free scattering
The breakthrough was enabled by a beamstop-free X-ray small-angle scattering technique. This method eliminated the conventional beam stop used to protect the camera from the direct X-ray beam. By removing this block, the technique expanded the measurable intensity range by more than 100 times compared to older methods.
This expansion allowed the detection of low-order diffraction signals that were previously inaccessible. The experiment successfully captured signals from the m = 0, ±1, and ±2 diffraction orders for the first time in such a setup.
Simulation insights reveal plasma size impact on energy absorption
Comparing the experimental data with simulations provided a key new insight into plasma-light interactions. The analysis showed that the initial size of the plasma has a dramatic effect on how it absorbs laser energy. According to the findings, a mere 10 nm increase in the initial plasma size reduces laser energy absorption by approximately one-fourth.
Applications in fusion and biological systems
The new diagnostic method supports single-shot multiscale measurements for high-energy-density plasmas. This capability is vital for studying complex phenomena like plasma instabilities and turbulence across multiple length scales simultaneously.
Potential applications are broad. In fusion energy research, the technique can elucidate plasma interactions with reactor walls. In biological studies, it allows the examination of solid-to-plasma transformations in samples like living cells, where minimal X-ray exposure is critical because the sample state changes over time. The method is particularly suited for any sample where repeated measurements are difficult.
The advancement closes on its core capability: enabling single-shot multiscale measurements for high-energy-density plasmas across nanoscale to microscale dimensions with sub-picosecond temporal resolution.
