Zap Energy sets record with gigapascal plasma pressures in FuZE-3 fusion reactor

Zap Energy has pushed plasma pressures to 830 megapascals in its latest fusion device, marking the highest performance yet for a sheared-flow-stabilized Z pinch. The achievement brings the Seattle company measurably closer to the fusion community’s holy grail of scientific energy gain.

The results came from FuZE-3, a device that represents a fundamental rethink of how Zap generates its fusion conditions. Total plasma pressure reached approximately 1.6 gigapascals, comparable to conditions deep below Earth’s crust or ten times the pressure at the bottom of the Mariana Trench. The plasma held these conditions for roughly a microsecond, measured using optical Thomson scattering.

FuZE-3 introduces a three-electrode architecture that separates the forces driving plasma acceleration from those controlling compression. Previous devices used a single electrical pulse between two electrodes, forcing engineers to use the same power for both accelerating plasma to create stabilizing flow and compressing it into the Z pinch configuration. This constrained density improvements despite effective heating.

The new design employs two capacitor banks feeding three electrodes, giving engineers independent control over these parameters. Colin Adams, head of experimental physics at Zap, describes it as gaining a new dial to tune the physics.

Multiple shots have now produced electron densities of 3 to 5 times 10²⁴ particles per cubic meter at temperatures exceeding 1 keV, equivalent to 21 million degrees Fahrenheit. Because plasmas contain both electrons and heavier ions at roughly equal temperatures, the total pressure doubles the electron measurements.

Pressure matters in fusion because it combines temperature with density, and higher pressures directly increase fusion reaction rates. Different approaches strike different balances. Zap targets a middle ground, and despite these high pressures, the physics remains in the quasi-steady-state magnetic confinement regime rather than the nanosecond inertial fusion of laser arrays.

Benn Levitt, vice president of R&D, credits the rapid progress to tightly coupled cycles of theoretical prediction, modelling, engineering and validation. The relatively compact scale enables faster iterations, and achieving comparable performance at a fraction of the size and cost amplifies the significance.

FuZE-3 was only recently commissioned yet already produces high-quality shots with strong repeatability. The earlier FuZE-Q remains in operation alongside it, while another device is scheduled to come online this winter.