Advances in inertial confinement fusion and innovative modeling have brought nuclear fusion closer to reality, offering insights into high-energy-density physics and the early universe.

The pursuit of controlled nuclear fusion as a source of clean, abundant energy is moving closer to realization, thanks to advancements in inertial confinement fusion (ICF). This method involves igniting deuterium-tritium (DT) fuel by subjecting it to extreme temperatures and pressures during a precisely engineered implosion process.

In DT fusion, most of the released energy is carried by neutrons, which can be harnessed for electricity generation. Simultaneously, alpha particles remain trapped within the fuel, where they drive further fusion reactions. When the energy deposited by these alpha particles surpasses the energy input from the implosion, the plasma enters a self-sustaining “burning” phase. This significantly boosts energy output and density.

Photons, electrons, and other particles can propagate as wave packets with helical wave fronts that carry an orbital angular momentum. These vortex states can be used to probe the dynamics of atomic, nuclear, and hadronic systems. Recently, researchers demonstrated vortex states of x-ray photons and proposed ways to realize such states for particles at higher energies (MeV to GeV). But verifying high-energy vortex states will be challenging, because characterization techniques used at lower energies would perform poorly. Zhengjiang Li of Sun Yat-sen University in China and his colleagues at Shanghai Institute of Optics and Fine Mechanics propose a new diagnostic method for high-energy vortex states. Their approach would reveal such states through an exotic scattering phenomenon called a superkick.

A superkick is a theorized effect occurring when an atom placed near the axis of a vortex light beam absorbs a photon. Under such conditions, the atom may get kicked to the side with a transverse momentum greater than that carried by the photon. Li and his colleagues considered a similar superkick involving electrons. They analyzed the elastic head-on collision of two electron wave packets at 10 MeV, one in a vortex state and the other in a nonvortex one. According to their calculations, two electrons in the beam, upon scattering, would acquire a nonzero total transverse momentum that could be detectable. The researchers predict an unmistakable signature of the vortex state: The momentum imbalance increases as the collision point gets closer to the vortex axis.

The researchers expect the superkick effect—which has never been observed—to be detectable with realistic experimental settings. They say the idea could be extended to high-energy vortices of photons, ions, and even hadrons.

How do you find and measure nuclear particles, like antineutrinos, that travel near the speed of light?

Antineutrinos are the antimatter partner of a neutrino, one of nature’s most elusive and least understood subatomic particles. They are commonly observed near nuclear reactors, which emit copious amounts of antineutrinos, but they also are found abundantly throughout the universe as a result of Earth’s natural radioactivity, with most of them originating from the decay of potassium-40, thorium-232 and uranium-238 isotopes.

When an antineutrino collides with a proton, a positron and a neutron are produced—a process known as inverse beta decay (IBD). This event causes scintillating materials to light up, making it possible to detect these antineutrinos; and if they can be detected, they can be used to study the properties of a reactor’s core or Earth’s interior.