The magnetic mirror fusion concept dates to the early 1950s, but decades ago it was sidelined by technical difficulties and researchers turned to tokamak fusion in their quest for confinement. Now it’s getting another look—with significantly more powerful technology—through WHAM, the Wisconsin HTS Axisymmetric Mirror, an experiment in partnership between startup Realta Fusion and the University of Wisconsin–Madison.

Lauren Garrison

We have seen many advancements in the fusion field in the past handful of years. In 2021, the National Academies released a report titled Bringing Fusion to the U.S. Grid.^a In March 2022, the White House held a first-ever fusion forum, “Developing a Bold Decadal Vision for Commercial Fusion Energy.”^b The National Ignition Facility had a record-setting fusion pulse that achieved more power output than the laser input, called ignition, in December 2022.^c The Department of Energy’s Office of Fusion Energy Sciences (FES) started a new public-private partnership program, the fusion milestone program, in May 2023 that made awards to eight fusion companies in a cost-share model.^d That same summer, FES got a new associate director, Dr. Jean Paul Allain,^e who has announced intentions for changing the structure of the FES office to better embrace an energy mission for fusion while keeping the strong foundation in basic science and non-fusion plasmas. ITER construction has continued, with various parts being delivered and systems finished. For example, the civil engineering of the tokamak building was completed in September 2023 after 10 years of work.^f Even more fusion companies have been founded, and the Fusion Industry Association has 37 members now.^g

Commonwealth Fusion Systems (CFS) and Tokamak Energy Inc. are the two magnetic confinement tokamak fusion developers to receive a portion of the $46 million in funding announced by the Department of Energy in late May for the first 18 months of a public-private Milestone-Based Fusion Development Program aimed at developing fusion pilot plant designs and resolving related scientific and technological challenges within five to 10 years.

From a crowded field of would-be fusioneers, the Department of Energy has selected eight companies for the public-private Milestone-Based Fusion Development Program to develop fusion pilot plant designs and resolve related scientific and technological challenges within five to 10 years. The DOE announced awards totaling $46 million for an initial 18 months of work on May 31.

One doesn’t typically come across nuclear fusion in a fashion magazine, but a recent issue of Vanity Fair profiled the creative director of a famous luxury fashion house who has made nuclear fusion a conceptual focus of her clothing creations. According to the article, Gabriela Hearst, the creative director at the New York City office of Paris-based Chloé, has designed a spring-summer 2023 collection “inspired by site visits to labs in the Pacific Northwest, New England, and southern France, where hundreds of scientists and engineers are working to develop technology that will produce a net energy gain through fusion.”

Commonwealth Fusion Systems (CFS) hosted visiting officials for a tour and ribbon-cutting ceremony to officially open its new headquarters in Devens, Mass., on February 10. Energy secretary Jennifer Granholm, Sen. Elizabeth Warren (D., Mass.), and Sen. Edward Markey (D., Mass.) were among the national, state, and local leaders invited to celebrate what CFS heralded as a “fusion energy campus.”

The Department of Energy’s Office of Science announced $2.3 million in funding on January 17 for 10 fusion energy projects that will allow private companies to work with national laboratories to address specific challenges in fusion energy development. Seven private companies and seven national laboratories are represented in the 10 projects selected for funding, provided through the INFUSE (Innovation Network for Fusion Energy) program. The second-round fiscal year 2022 awards follow a first round of 18 project awards announced in July 2022.

The Massachusetts Institute of Technology’s Plasma Science and Fusion Center (PSFC) recently announced it will expand its involvement in fusion energy research and education under a new five-year agreement with Commonwealth Fusion Systems (CFS), a fusion energy company that got its start at MIT and is now building what it says will be the world’s first net-energy fusion machine—the demo-scale SPARC.

“CFS will build SPARC and develop a commercial fusion product, while MIT PSFC will focus on its core mission of cutting-edge research and education,” said PSFC director Dennis Whyte in describing the collaboration.

The Department of Energy has selected eight private industry projects for fusion energy collaboration with DOE national laboratories. The awards are provided through the Innovation Network for Fusion Energy (INFUSE), which focuses on five areas of research: enabling technologies; materials; diagnostics; modeling and simulation; and experimental capabilities.

Paul Dabbar, former undersecretary for science at the Department of Energy and distinguished visiting fellow at Columbia University’s Center on Global Energy Policy, is lauding the recent successful test of a 10-ton high-temperature superconducting magnet performed by researchers at the Massachusetts Institute of Technology and Commonwealth Fusion Systems. In an op-ed published on September 10 in The Hill, Dabbar calls for a new level of investment and support for the commercial fusion sector.

A high-temperature superconducting magnet reached and maintained a magnetic field of more than 20 tesla in steady state for about five hours on September 5 at MIT’s Plasma Science and Fusion Center. Not only is the magnet the strongest high-temperature superconducting (HTS) magnet in the world by far, it is also large enough—when assembled in a ring of 17 identical magnets and surrounding structures—to contain a plasma that MIT and Commonwealth Fusion Systems (CFS) hope will produce net energy in a compact tokamak device called SPARC in 2025, on track for commercial fusion energy in the early 2030s.

The Department of Energy’s Office of Science has named seven companies as the recipients of cost-shared funding granted through the Innovation Network for Fusion Energy (INFUSE). A total of $2.1 million in first-round fiscal year 2021 funding was awarded on July 1 across nine collaborative projects between DOE national laboratories and private industry aimed at overcoming challenges in fusion energy development.

Rendering of SPARC, a compact, high-field, DT burning tokamak, currently under design by a team from MIT and CFS. Source: CFS/MIT-PSFC - CAD Rendering by T. Henderson

The fusion community is reaching a "Kitty Hawk moment" as early as 2025, according to the Popular Mechanics story, "Jeff Bezos Is Backing an Ancient Kind of Nuclear Fusion."

That moment will come from magnetized target fusion (MTF), the January 25 story notes, a technology that dates back to the 1970s when the U.S. Naval Research Laboratory first proposed it. Now, however, MTF’s proponents say that the technology is bearing down to reach the commercial power market. The question is, Will it be viable before the competing fusion model of tokamaks, such as ITER, start operations?

Cutaway of the SPARC engineering design. Image: CFS/MIT-PSFC, CAD rendering by T. Henderson

Seven open-access, peer-reviewed papers on the design of SPARC, Commonwealth Fusion Systems’ (CFS) fusion tokamak, written in collaboration with the Massachusetts Institute of Technology’s Plasma Science and Fusion Center, were published on September 29 in a special edition of the Journal of Plasma Physics.

The papers describe a compact fusion device that will achieve net energy where the plasma generates more fusion power than used to start and sustain the process, which is the requirement for a fusion power plant, according to CFS.

The timeline for this planned device sets it apart from other magnetic confinement fusion tokamaks: Construction is to begin in 2021, with the device coming on line in 2025.

CFS expects the device to achieve a burning plasma—a self-sustaining fusion reaction—and become the world’s first net energy (Q>1) fusion system. The newly released papers reflect more than two years of work by CFS and the Plasma Science and Fusion Center to refine their design. According to CFS, the papers apply the same physics rules and simulations used to design ITER, now under construction in France, and predict, based on results from existing experiments, that SPARC will achieve its goal of Q>2. In fact, the papers describe how, under certain parameters, SPARC could achieve a Q ratio of 10 or more.

Cutaway of the SPARC engineering design. Image: CFS/MIT-PSFC, CAD Rendering by T. Henderson

A special issue of the Journal of Plasma Physics gives a glimpse into the physics basis for SPARC, the DT-burning tokamak being designed by a team from the Massachusetts Institute of Technology and Commonwealth Fusion Systems. The special issue was announced in a September 29 post on the Cambridge University Press blog Cambridge Core.

The special JPP issue includes seven peer-reviewed articles on the SPARC concept, which takes advantage of recent breakthroughs in high-temperature superconductor technology to burn plasma in a compact tokamak design.