An exotic version of matter called a nanoplasma has been caught in the act of forming for the first time.
When a pulse of high-energy X-rays strikes a cluster of a few thousand atoms, it strips and scatters the atoms’ electrons, creating a gas of ions called a nanoplasma. The plasma is so short-lived that observing its birth has proved difficult.
Kiyoshi Ueda at Tohoku University in Japan and his colleagues delivered a powerful but brief pulse of X-rays to a nanometre-scale cluster of xenon atoms. This pulse was swiftly followed by a flash of near-infrared light, which enabled the researchers to observe the nanoplasma’s formation.
The X-ray pulse stripped the xenon atoms of some of their electrons to form a nanoplasma — a process that took less than 12 quadrillionths of a second, according to the team's observations. The pulse also created many highly excited atoms, which collided to form more ions within a few hundred quadrillionths of a second.