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Proton beams with giga-electron-volt (GeV) energies—once thought to be achievable only with massive particle accelerators—may soon be generated in compact setups thanks to a breakthrough by researchers at The University of Osaka.

A team led by Professor Masakatsu Murakami has developed a novel concept called micronozzle acceleration (MNA). By designing a microtarget with tiny nozzle-like features and irradiating it with ultraintense, ultrashort laser pulses, the team successfully demonstrated—through advanced numerical simulations—the generation of high-quality, GeV-class proton beams: a world-first achievement.

The article, "Generation of giga-electron-volt proton beams by micronozzle acceleration," was in Scientific Reports.

Unlike traditional laser-based acceleration methods that use flat targets and reach energy limits below 100 mega-electron-volt (MeV), the micronozzle structure enables sustained, stepwise acceleration of protons within a powerful quasi-static electric field created inside the target. This new mechanism allows proton energies to exceed 1 GeV, with excellent beam quality and stability.

"This discovery opens a new door for compact, high-efficiency particle acceleration," says Prof. Murakami. "We believe this method has the potential to revolutionize fields such as laser fusion energy, advanced radiotherapy, and even laboratory-scale astrophysics."

The implications are wide-reaching:

• Energy: Supports fast ignition schemes in laser-driven nuclear fusion.
• Medicine: Enables more compact and precise systems for proton cancer therapy.
• Fundamental science: Creates conditions to simulate extreme astrophysical environments and probe matter under ultra-strong magnetic fields.

The study, based on simulations performed on the SQUID supercomputer at The University of Osaka, marks the first-ever theoretical demonstration of compact GeV proton acceleration using microstructured targets.