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June 4, 2026by Stephen Shankland [Head of Content | @stshank]<br>With the publication today of five deeply researched and peer-reviewed papers, Commonwealth Fusion Systems (CFS) and dozens of collaborating physicists have cemented our confidence in the core plasma physics assumptions at work within our upcoming ARC fusion power plant.<br>Fusion energy, the power source of the sun and other stars, has plenty of challenges here on Earth. We’ll need to control a superhot fusion fuel called a plasma — an intensely dynamic cloud of charged particles. But these papers show how we’ll handle those plasma physics challenges so we can bring this clean, secure, abundant source of energy to the electricity grid — the last form of energy that humanity will need.<br>The five papers are the culmination of our methodical work to deliver fusion power plants at scale. The papers:<br>build on decades of research that gave us a head start on the type of fusion machine we’re building now, called a tokamak<br>blend in what we’ve learned already from the SPARC tokamak we’re building in Massachusetts to demonstrate net fusion energy, aka Q>1, then go beyond that to prove our technology<br>apply advanced simulations and calculations to show how our ARC plants will generate power and manage the plasma physics<br>benefit from the peer review process’ independent validation, anchoring our own confidence<br>The scientifically rigorous papers, with 58 co-authors, span 226 pages in a special edition of the the Journal of Plasma Physics. They detail how an ARC plant will produce roughly 1.1 gigawatts (GW) of fusion power that we’ll convert into 400 megawatts (MW) of net electricity delivered continuously to the grid — enough to power about 280,000 average American homes.<br>With our physics capabilities now established, CFS has begun devoting more attention to designing and engineering the ARC plant. As with the tokamak’s physics, that effort is an extension of the SPARC project. By design, the two tokamaks are similar so we can transfer what we’ve learned directly from SPARC to its successor. Once SPARC works, we know ARC plants will, too.<br>These are the five ARC physics basis papers (and keep on reading if you want a detailed look at each):<br>Overview of the physics basis for the ARC fusion power plant<br>Power and particle exhaust for the ARC fusion power plant<br>ARC cisruption physics and strategy<br>Performance and transport in the ARC tokamak<br>ARC physics basis — magnetohydrodynamics<br>The papers join a list of CFS achievements since our 2018 founding. Among them: building the world’s strongest superconducting magnet for fusion; designing our SPARC fusion demonstration machine; developing a supply chain of critical components; building and running our magnet factory; beginning SPARC assembly; selecting a site in Virginia for our Fall Line Fusion Power Station; signing on Google as our first commercial customer and Italy-based energy company Eni as another; and applying to connect our ARC plant to PJM Interconnection to make it the first grid-scale fusion power plant in the world.<br>This record of steady execution, underpinned by our SPARC experience, is the basis for our confidence in our ability to meet our goal of bringing fusion power to the electricity grid at scale as soon as possible.<br>A midplane illustration of Commonwealth Fusion Systems’ ARC tokamak<br>A quintet of fusion physics papers<br>Four of the papers dig into major aspects of the plasma physics of the ARC plant, detailing the behavior of the plasma itself and ways we’ll handle challenges like exhaust heat and plasma disruptions. The fifth paper offers an overview that combines the other papers’ findings and shows our confidence that we’ll be able to produce more than a gigawatt of fusion power.<br>Through this process, we’ve shown that the ARC power plant agrees with known physics, that it successfully extends SPARC’s lineage, and that we have the physics tools to further refine the ARC design. Both the SPARC and ARC machines are donut-shaped devices called a tokamak.<br>“We are laying out, arguably for the first time, a realistic physics design point for a commercially relevant fusion power plant,” said Alex Creely, Chief Engineer of ARC Conceptual Design at CFS and author of an editorial accompanying the ARC physics basis papers. “These papers show why CFS and our partners are confident in the physics underlying the ARC fusion power plant. Designing a fusion power plant that we truly intend to build soon means that we had to ask the right questions, sharpen our tools, and focus on the top priority information that SPARC will teach us.”<br>We’ll keep using those tools, too. The papers show how...