Lattice confinement fusion (LCF) is a type ofnuclear fusion in whichdeuteron-saturated metals are exposed togamma radiation or ion beams avoiding the confined high-temperature plasmas used in other methods of fusion.^[1][2]

In 2020, a team ofNASA researchers seeking a new energy source for deep-space exploration missions published the first paper describing a method for triggering nuclear fusion in the space between the atoms of a metal solid, an example of screened fusion.^[3] The experiments did not produce self-sustaining reactions, and the electron source itself was energetically expensive.^[1]

The reaction is fueled withdeuterium (²H), a stableisotope of hydrogen composed of oneproton, oneneutron, and oneelectron. The deuterium is confined in the space between the atoms of a metal solid such aserbium ortitanium. Erbium can indefinitely maintain 10²³ cm⁻³ deuterium atoms at room temperature. The deuteron-saturated metal forms an overall neutralplasma.^{[dubious –discuss]} Theelectron density of the metal reduces the likelihood that two deuterium nuclei (deuterons) will repel each other as they get closer together.^[1]

Adynamitron electron-beam accelerator generates anelectron beam that hits atantalum target and producesgamma rays, irradiating titanium deuteride or erbium deuteride. A gamma ray of about 2.2 megaelectronvolts (MeV) strikes a deuteron and splits it into proton and neutron. The neutron collides with another deuteron. This second, energetic deuteron can experience screened fusion or a stripping reaction.^[1]

Though the lattice is notionally at room temperature, LCF creates an energetic environment inside the lattice where individual atoms achieve fusion-level energies.^[3] Heated regions are created at themicrometer scale.

The energetic deuteron fuses with another deuteron, yielding either a³He nucleus and a neutron or a³H nucleus and a proton. These fusion products may fuse with other deuterons, creating an alpha particle, or with another³He or³H nucleus. Each releases energy, continuing the process.^[1]

In a stripping reaction, the metal strips a neutron from accelerated deuteron and fuses it with the metal, yielding a different isotope of the metal.^[1] If the produced metal isotope is radioactive, it may decay into another element, releasing energy in the form ofionizing radiation in the process.

A related technique pumps deuterium gas through the wall of apalladium-silver alloy tubing. The palladium is electrolytically loaded with deuterium. In some experiments this producesfast neutrons that trigger further reactions.^[1] Other experimenters (Fralick et al.) also made claims of anomalous heat produced by this system.

Pyroelectric fusion has previously been observed in erbium hydrides. A high-energy beam of deuterium ions generated by pyroelectric crystals was directed at a stationary, room-temperature Er²H₂ or Er³H₂ target, and fusion was observed.^[2]

In previous fusion research, such asinertial confinement fusion (ICF), fuel such as the rarertritium is subjected to high pressure for a nano-second interval, triggering fusion. Inmagnetic confinement fusion (MCF), the fuel is heated in a plasma to temperatures much higher than those at the center of the Sun. In LCF, conditions sufficient for fusion are created in a metal lattice that is held at ambient temperature during exposure to high-energyphotons.^[3] ICF devices momentarily reach densities of 10²⁶ cc⁻¹, while MCF devices momentarily achieve 10¹⁴.

Lattice confinement fusion requires energetic deuterons and is therefore notcold fusion.^[1]

• Inertial confinement fusion
• Magnetized target fusion
• Pyroelectric fusion

• Nuclear fusion
• Nuclear fusion reactions
• Deuterium
• Erbium
• NASA research centers
• Space exploration

• Source attribution
• Articles with short description
• Short description matches Wikidata
• All accuracy disputes
• Articles with disputed statements from February 2023