Our eyes, ears, and fingertips are good for figuring out a lot of what’s going on around us. But to understand the inner workings of a fusion energy machine, you need more than human senses. That’s where diagnostic equipment comes into play — the tools you need to get things right and sidestep avoidable blunders. Here’s a look at how we use diagnostics at Commonwealth Fusion Systems (CFS). In fusion, the complex process that powers the sun, lightweight elements like hydrogen combine to produce heavier elements and tremendous amounts of energy. Fusion fuel on Earth is the same type of matter that the sun is made of: a plasma, which is a superhot cloud of fast-moving charged particles. You can’t just watch a plasma fuse the way you can watch an apple falling or an ice cube melting. Happily, at CFS, we’re able to take advantage of hard-won knowledge about observing neutrons, light, heat, magnetic fields, and other physical phenomena to understand our machine. “A high-temperature plasma is giving off copious amounts of information about itself, broadcasting its behavior,” says Matt Reinke, leader of the SPARC diagnostics team. “It's remarkable how it can be probed physically or with electromagnetic waves to tell you even more.” The knowledge sharing continues this week at the 26th High Temperature Plasma Diagnostics (HTPD) conference in Cambridge, Massachusetts. There, CFS researchers are showing our newest work on diagnostics for SPARC, the machine we’re building right now to demonstrate net fusion energy. Diagnostic approaches are documented through the peer-reviewed research process, and we use that independent scrutiny to ensure we’re on the right track, too. Misunderstanding your machine can lead to mistakes — like U.K. researchers having to correct their assessment of their Zeta experiment’s results in fusion’s earliest days in the 1950s. But we’ve learned a lot since then about setting up diagnostic equipment to get it right — like when a later U.K. team confirmed that a Soviet tokamak really was as powerful as its creators claimed. And that knowledge clears the way for fusion to progress at full speed. #FusionEnergy #Diagnostics #Plasma

Today, we laid the physics foundation for our ARC fusion power plant. ⚛️ With 5 deeply researched papers — validated by independent peer review and published in the Journal of Plasma Physics — we’ve shown we've nailed the scientific basics of producing copious amounts of fusion power. The collective assessment from our 58 co-authors? This machine will work. No scientific breakthroughs are required to bring this clean, secure, abundant source of energy to the grid. Here is how we're handling fusion's biggest challenges: ⚡ Powering the Grid: Using extremely strong magnets, ARC will confine the plasma long enough to generate 1.1 GW of fusion power. We'll convert that into 400 MW of continuous net electricity — enough to power ~280,000 average American homes. 🛡️ Handling Heat Exhaust: To control a superhot, unruly cloud of charged particles, we're utilizing proven methods to safely handle the heat exhaust that acts as a key practical constraint for tokamaks. ✅ Managing Disruptions: We aren't trying to build an operationally perfect machine. We are pragmatically designing ARC to safely handle disruptions and keep the plasma stable for top performance. 🏗️ Proving the Approach: We're building on decades of tokamak research and supercomputer simulations. And we're proving our approach right now with SPARC, the tokamak we are actively building in Massachusetts. With our transparency, you don’t have to take our assertions on faith. We are really pushing fusion forward.

Kudos to the @ENERGY for pushing forward this effort to build a volumetric neutron source, a facility that would help many companies in the fusion energy business move faster, for example by evaluating materials science options. This facility has been a longstanding item in DOE Science and Technology road maps, with a well understood needs and benefits, and fusion energy's benefits will come sooner with it up and running. This facility also would help supply DOE's Genesis Mission with data that'll help AI supercharge energy research. Some Genesis Mission background: energy.gov/documents/genesis… And if you're curious, here's DOE's most recent Science & Technology roadmap for fusion: energy.gov/sites/default/fil… This DOE work all helps commercial fusion deploy and scale more quickly. #FusionEnergy #Energy

Today we announced a new strategic agreement with the Singapore-based Agency for Science, Technology and Research, @ASTARsg. This five-year collaboration is designed to develop technologies for commercial fusion power plants, including CFS’ ARC power plants, and will also help Singapore's effort to be an early entrant in the global fusion energy supply chain. This agreement builds on an earlier collaboration with ST Engineering, also headquartered in Singapore, to produce components for our prototype fusion machine, SPARC. "Singapore possesses major capabilities in advanced manufacturing and materials engineering," says CFS CEO and Co-founder @BobMumgaard. "They've deployed these capabilities in the shipbuilding, aerospace, and semiconductor sectors. With our partnership with A*STAR, we envision that these capabilities will accelerate our commercialization journey." Beyond fusion, the partnership will develop capabilities in materials science, advanced manufacturing, and plasma diagnostics that are useful for industries operating under similarly demanding environments — aerospace and other advanced engineering sectors, for example. #FusionEnergy #Energy

Now that both halves of our vacuum vessel are here, our team is deep in the work of preparing each half for assembly into our SPARC fusion machine. That means a whole lot of cleaning and measuring, then furnishing each half with diagnostic equipment and plasma-facing components. These photos show the interior of the vessel, including hundreds of studs where we'll attach the plasma-facing components and one of the "divertor" areas that'll help handle the tokamak's hot helium exhaust. The vacuum vessel combines strength, durability, and precision to serve several critical functions — creating an effective vacuum for the plasma inside SPARC, withstanding the extreme temperatures required to sustain a fusion reaction, and shouldering colossal forces exerted by SPARC’s magnets. Stay tuned for a more detailed look soon at what we're up to with the vacuum vessel. #FusionEnergy #Energy #Physics #Science