Zap Energy Exceeds Gigapascal Fusion Plasma Pressures on New Fusion Device, FuZE-3

Zap Energy, building a seriously cheap, compact, scalable fusion energy technology, led by Benj Conway, Brian A. Nelson, and Uri Shumlak, has achieved plasmas with electron pressures as high as 830 megapascals (MPa), or 1.6 gigapascals (GPa) total, comparable to the pressures found deep below Earth’s crust. The results are the highest-pressure performance to date in a sheared-flow-stabilized Z pinch and an important marker on the path to scientific energy gain, or Q>1.

FuZE-3, Zap’s first device with a third electrode to separate plasma acceleration and compression forces, showed promising early results presented at the APS Division of Plasma Physics meeting in Long Beach, Calif.

“FuZE-3 introduces major changes compared to previous systems, and it’s impressive to see such strong performance so early,” said Colin Adams, Head of Experimental Physics.

Fusion energy relies on extremely hot, dense plasma, where high pressure, combining temperature and density, is key to driving reactions. Zap’s sheared-flow-stabilized Z pinches balance compression and confinement, aiming for an optimal middle ground.

The highest single-shot electron pressure recorded is 830 MPa. Accounting for ions, total plasma pressure could reach roughly 1.6 GPa, about 10,000 times atmospheric pressure or ten times the pressure at the Mariana Trench, sustained for a microsecond. Measurements were made using optical Thomson scattering, the gold standard for plasma pressure diagnostics.

Recent FuZE-3 campaigns achieved electron densities of 3–5×10²⁴ m⁻³ and electron temperatures above 1 keV (≈21 million °F). Ben Levitt, VP of R&D, highlighted that this success came from a tightly coupled cycle of theory, modeling, rapid engineering, experimental validation, and measurement. Achieving these results in a compact, lower-cost system underscores the significance of the accomplishment.

FuZE-3, the third generation of FuZE devices and fifth sheared-flow-stabilized Z-pinch, follows Zap’s original FuZE, the first to exceed 1 keV temperatures, and FuZE-Q, the highest-performing device by power and fusion neutron yield, which remains operational. Designed to reach new triple product levels (density × temperature × confinement time), FuZE-3 features three electrodes and two capacitor banks to advance fusion performance.

Previous tests at Zap used two-electrode systems, where a single pulse of current both accelerated and compressed plasma. This dual role limited the ability to achieve targeted compression. FuZE-3’s design separates acceleration from compression, giving precise control to increase plasma density. While pressures are high, Zap’s quasi-steady-state magnetic confinement focuses on sustained stabilizing flow, unlike inertial fusion systems that rely on nanosecond compression with powerful lasers or Z pinches.

FuZE-3 results are preliminary as campaigns continue. Data is being shared at the APS DPP meeting, with formal publication planned in the coming months. High-quality, repeatable shots show strong headroom for improving fusion performance, with lessons from FuZE-3 informing next-generation devices. Another new FuZE system is scheduled for commissioning this winter, while Century platform development for power plant engineering progresses in parallel.