Eric Lander
Data verified as of Aug 1, 2026
Pacific Fusion is taking the inertial route to fusion rather than the magnetic one: instead of holding plasma in a magnetic bottle, it crushes a small capsule of deuterium-tritium fuel with an enormous, extremely fast electrical pulse. The company's distinguishing technology is the impedance-matched Marx generator, a pulser architecture that is simpler and cheaper than the systems used at national laboratories, and its plan is to gang 156 production-scale pulser modules into a Demonstration System designed to reach net facility gain - more fusion energy out than the total energy stored in the machine - by 2030. Founded in 2023 by Eric Lander, Keith LeChien, Will Regan, Carrie von Muench and Leland Ellison, it launched publicly in October 2024 with a roughly $900M Series A led by General Catalyst that is released in tranches against technical milestones; the round has since passed $1B as those milestones cleared. In June 2026 a scaled module prototype delivered more than 440 gigawatts at about 1.1 megavolts in an 80-nanosecond pulse, and in July 2026 the Sirius prototype at Lawrence Livermore National Laboratory passed 3,000 full-power shots at 95% energy efficiency. Its $1B research and manufacturing campus at Mesa del Sol in Albuquerque, New Mexico, backed by a build center in Los Lunas, is where the Demonstration System will be assembled.
Pacific Fusion's first-of-a-kind machine, to be assembled at the $1B Mesa del Sol campus in Albuquerque from 156 production-scale pulser modules (each 32 circular stages ringed with 10 bricks). It is designed to reach net facility gain, producing more fusion energy than the total energy stored in the system, and to do it at roughly 100x the facility gain of the National Ignition Facility for about a tenth of the cost.
Pre-construction. Ground is due to be broken on the Albuquerque campus in August 2026, with components already being produced at the Los Lunas build center opened in December 2025 and a full-scale module prototype (about 40x the size of Sirius) in build. Net facility gain is targeted by 2030. The company stresses this is a demonstration machine, not a power plant.
The repeating building block of the Demonstration System: an impedance-matched Marx generator that stacks capacitor-and-switch 'bricks' into stages and synchronizes them into a single ultra-fast, high-current pulse. Getting one module right and then manufacturing it 156 times is the company's whole scaling strategy.
A scaled prototype at about one third of full module size (nine stages, 90 bricks) delivered more than 440 GW at ~1.1 MV in an 80-nanosecond pulse in June 2026, meeting the requirements for scaling to the full Demonstration System and unlocking a further Series A tranche. A full-scale module prototype is now in build.
The four-stage impedance-matched Marx generator prototype built at Lawrence Livermore National Laboratory under a cooperative research agreement. Sirius synchronizes electromagnetic waves onto a transmission line in a single step, which is what makes the architecture simpler and more efficient than conventional pulsed-power systems, and it is the machine that generated the empirical data validating Pacific Fusion's simulations.
Completed 3,000 full-power shots by July 2026, delivering 60 GW in a 100-nanosecond pulse at 95% energy efficiency. The June 2026 scaled prototype is roughly an 11x scale-up of Sirius, and the full-scale module now in build is about 40x its size.
Pacific Fusion and Lawrence Livermore National Laboratory reported that Sirius, their four-stage impedance-matched Marx generator prototype, has completed 3,000 full-power shots, each delivering 60 gigawatts in a 100-nanosecond pulse at 95% energy efficiency. The reliability campaign provides the empirical base for the much larger 156-module Demonstration System Pacific Fusion is targeting for net facility gain by 2030.
Development stage. Pulser modules are being assembled and tested at the Bay Area R&D campuses, the Sirius prototype at Lawrence Livermore has passed 3,000 full-power shots, and the June 2026 scaled module prototype validated the architecture at roughly one third of full module scale. The company is now building a full-scale prototype about 40x the size of Sirius and breaking ground on the Albuquerque campus in August 2026, with the 156-module Demonstration System targeted to reach net facility gain by 2030. The Demonstration System is explicitly not a power plant.
Milestone-tranched venture capital
A Series A led by General Catalyst that now exceeds $1B, released against pre-agreed technical milestones rather than in a lump sum, which the company says lets the team stay on engineering rather than continuous fundraising.
National laboratory partnerships
Cooperative research and development agreements with Sandia National Laboratories (Z Pulsed Power Facility, December 2024) and Lawrence Livermore National Laboratory (January 2025), plus an April 2025 partnership with General Atomics on inertial fusion energy, giving Pacific Fusion access to facilities and expertise it would otherwise have to build.
Employees
Not publicly disclosed
On February 5, 2026 Pacific Fusion reports results from experiments at Sandia's Z Pulsed Power Facility showing that a much simpler target - plastic wrapped in aluminium, letting the magnetic field diffuse in to pre-magnetize the fuel - can work in place of more complex designs, removing external laser and magnet hardware and cutting the cost and maintenance burden of a system that has to fire repeatedly.
On June 2, 2026 the company reports that a scaled module prototype - nine stages of 90 bricks, about one third of a full module - delivered more than 440 gigawatts of peak power at roughly 1.1 megavolts in an 80-nanosecond pulse, with a low-cost trigger system synchronizing every stage into a single coherent pulse. The result unlocked a further tranche of the Series A, taking the round past $1B.
On July 16-17, 2026 Pacific Fusion and Lawrence Livermore report that Sirius, the four-stage impedance-matched Marx generator prototype built under their CRADA, has completed 3,000 full-power shots, delivering 60 gigawatts in a 100-nanosecond pulse at 95% energy efficiency. The campaign is the empirical base for the simulation models behind the far larger Demonstration System.
Adds a January 2025 cooperative agreement with Lawrence Livermore National Laboratory, then in April 2025 publishes its AMPS framework (affordable, manageable, practical, scalable) describing a demonstration system designed for 100x higher facility gain at 10x lower cost than the National Ignition Facility - what the company calls a 1,000-fold leap in practical fusion performance. A partnership with General Atomics follows the same month.
In September 2025 Pacific Fusion publishes four peer-reviewed papers in Physics of Plasmas validating its simulation stack against six benchmarks spanning hydrodynamic instabilities, fuel compression, confinement and ignition-scale inertial fusion target modelling - the first time a private fusion company has published validation across all of those processes.
On September 26, 2025 New Mexico's governor announces Pacific Fusion's $1B research and manufacturing campus at Mesa del Sol in Albuquerque, which will house the Demonstration System and is expected to create about 200 permanent jobs and roughly 1,000 construction jobs. A build center in Los Lunas producing components for the system opens that December.
The company emerges from stealth on October 25, 2024 with a roughly $900M Series A led by General Catalyst, structured to release capital in tranches as technical milestones are met. Backers include Breakthrough Energy Ventures, Ken Griffin, Patrick Collison, John Doerr and Mustafa Suleyman; Patrick Collison, Hemant Taneja and Eric Schmidt join the board.
Signs a cooperative research and development agreement with Sandia National Laboratories in December 2024, giving it access to the Z Pulsed Power Facility, the world's most powerful pulsed-power machine and the reference point for magnetically driven inertial fusion.
Commonwealth Fusion Systems
Nuclear Fusion
Commonwealth Fusion Systems is building commercial fusion systems around high-temperature superconducting magnet technology developed with MIT. SPARC, its fusion-energy demonstration tokamak under construction in Devens, Massachusetts, hit ~75% completion in 2026: the first of 18 toroidal-field magnets was installed in January and the second 48-ton vacuum-vessel half arrived in May, with all 18 magnets targeted by end of summer 2026 ahead of first plasma and a Q>1 net-energy attempt in 2027. ARC, CFS' first commercial plant - officially named the Fall Line Fusion Power Station and sited on 100 acres in Chesterfield County, Virginia - became in April 2026 the first fusion project to file for grid interconnection with PJM, and on June 4, 2026 CFS published a five-paper ARC Physics Basis in the Journal of Plasma Physics projecting ~1.1 GW of fusion power and ~400 MW of net electricity. CFS has also begun monetizing its HTS magnet platform, signing a potentially multi-billion-dollar long-term magnet supply deal with Realta Fusion and launching a SPARC digital twin program with Nvidia and Siemens, and in July 2026 became the first international partner in the UK Atomic Energy Authority's £220M LIBRTI tritium-breeding program to tackle fusion's fuel-supply challenge.
Helion Energy
Nuclear Fusion
Helion Energy is building fusion generators aimed at producing commercial electricity from fusion. Its Polaris prototype began operating in late 2024 and in February 2026 became the first privately developed fusion machine to demonstrate measurable deuterium-tritium fusion at 150 million degrees Celsius. Helion is now advancing Orion in Malaga, Washington, where site work began in 2025 for the company's first commercial machine intended to deliver electricity from fusion to Microsoft, while a smaller new 'Tiny Merge' testbed is being built to iterate on plasma formation faster. On June 4, 2026 Helion closed a $465M Series G led by Thrive Capital at a $15.5B post-money valuation, lifting total funding to roughly $1.5B; OpenAI is in advanced talks to buy fusion power from Helion at gigawatt scale, prompting Sam Altman to step down as board chair to recuse himself from those negotiations.
Proxima Fusion
Nuclear Fusion
Proxima Fusion is Europe's best-funded fusion company and the first research spin-off from the Max Planck Institute for Plasma Physics, founded in Munich in 2023 to commercialize the stellarator - a twisted magnetic bottle that is harder to build than a tokamak but runs continuously without needing to drive a current through the plasma. Its quasi-isodynamic design, Stellaris, was published in February 2025 as the first peer-reviewed, fully integrated stellarator power plant concept. In February 2026 Proxima signed a memorandum of understanding with RWE, the Free State of Bavaria and the Max Planck IPP to build Alpha, a roughly €2B net-energy demonstrator at Garching near Munich targeted to begin operating in 2031, followed by a commercial Stellaris plant at the decommissioned Gundremmingen nuclear site later in the 2030s; an Alpha Alliance of more than 30 European industrial companies including Siemens Energy, Framatome, Air Liquide and Thales was announced the day before. On July 7, 2026 the company raised €411M ($468M) at a €2.4B ($2.7B) valuation, led by XTX Ventures and East X Ventures with RWE and Google as strategic investors, taking total funding past €650M and funding completion of its Stellarator Model Coil in 2027.
TAE Technologies
Nuclear Fusion
TAE Technologies is a private fusion company developing hydrogen-boron fusion with a beam-driven field-reversed-configuration architecture. Its 2025 'Norm' breakthrough reduced reactor complexity enough to skip the planned Copernicus step and move directly toward Da Vinci, its first prototype power plant. In 2026 TAE completed its multi-state site evaluation tour for the first 50 MWe plant (Alabama, Ohio, Texas), formally established the TAE Beam UK joint venture with UKAEA at Culham to commercialize neutral-beam accelerator technology, and is now targeting a Q4 2026 close of its $6B all-stock merger with Trump Media & Technology Group, which in June 2026 confirmed it will no longer spin off Truth Social and other media assets ahead of the deal. TAE Power Solutions and TAE Life Sciences commercialize adjacent power-delivery and oncology technologies derived from its fusion R&D.
Tokamak Energy
Nuclear Fusion
Tokamak Energy is a UK fusion company spun out of the UK Atomic Energy Authority in 2009 that pairs two bets: the spherical tokamak, a squashed-sphere reactor shape that holds plasma more efficiently than a conventional doughnut, and high-temperature superconducting (HTS) magnets built in-house. Its ST40 machine reached 100 million degrees Celsius in 2022 and closed out its 2025 campaign with three records - 1 mega-amp of plasma current, its highest stored energy, and a fusion triple product up over 30% to about 8 x 10^18 m^-3 keV s - before entering a $52M upgrade co-funded with the U.S. Department of Energy and the UK's DESNZ that runs through most of 2026. On the magnet side, Demo4 became in November 2025 the first HTS magnet system to reproduce fusion-relevant fields at system level (11.8 tesla, 7 million ampere-turns), and in April 2026 Tokamak Energy was named Magnet Systems Partner for the UK government's STEP prototype power plant under a £70M contract running to March 2029. The company sells that magnet capability commercially through TE Magnetics, which acquired manufacturer Ridgway Machines in 2025, and its roadmap runs ST40 to the ST80-HTS prototype at Culham and then to ST-E1, a pilot plant designed to put up to 200 MW of electricity on the grid in the early 2030s.