This week, The Fusion Report returns with the fourth article in our “The Fusion Decathlon” series, where we continue to explore magnetic fusion energy (MFE) solutions. If MFE companies were a group of runners, then they would be everything from sprinters, hurdlers, and 1.6 kilometer runners (also known as “milers”), all the way to marathon runners. Similarly, MFE solutions come in a variety of sizes, types and capabilities. Last week, we explored tokamaks and stellarators; let’s use this week’s article to dive into some variants of MFE solutions, including Z-pinch machines, field-reversed configuration (FRCs) machines, and magnetic mirrors.
Z-Pinch Machines: Harnessing the Power of Lightning
Z-pinch machines (also known as sheared flow stabilized Z-Pinch fusion machines) do not require any magnets, cryogenics or high power lasers to work. Rather, a Z-pinch machine utilizes the current flow in a hollow conductor to create a very strong magnetic field. The phenomenon was discovered in 1905 when two Australian scientists found a hollow lightning rod from a kerosene factory that had been crushed and twisted after being hit by a lightning bolt.
Basically the concept is that if you run a powerful enough current through a plasma, the Z-pinch effect can create conditions hot enough and dense enough for fusion to occur. The challenge is to hold the plasma together for long enough that fusion occurs. While Z-pinch fusion was tested as far back as the 1950s, it was the use of shear flow stabilization that allowed the plasma to be stabilized for an extended time. This shear flow stabilization technique was pioneered by Zap Energy, working in conjunction with Lawrence Livermore National Laboratories (LLNL) and Sandia National Labs, the offshoot of the Los Alamos Labs Manhattan Project. Zap is actively operating its FuZE-Q and newer FuZE-3 devices, achieving 39 kW average power with 10,000+ shots in a 2024-2025 campaign. The company has raised roughly $330 million since it was founded in 2017.
Field-Reversed Configurations: Self-Stable Magnetic Confinement
A field-reversed configuration (FRC) confines a plasma on closed magnetic field lines without a central penetration. In a sense, it is much like a smoke ring in that it is self-stabilizing. FRCs use cylindrical chambers rather than toroid-type chambers as in a tokamak or a stellarators, allowing FRCs to have a variety of scalable geometries. FRCs are also known for having very high beta values (the ratio of plasma pressure to magnetic pressure), typically approaching a beta of one. FRCs often use a number of approaches to achieve field reversal, including field reverse theta pinch, neutral beam injection, and rotating magnetic fields. Because of their high beta, a number of people are looking at FRCs for using with aneutronic fuels such as deuterium-helium3 (D-He3) or proton-boron11 (p-B11), though significantly higher temperatures are required for fusion than is required for deuterium-tritium (D-T) fusion.
The companies most known for working on FRC solutions are TAE Technology, who is pursuing p-B11 fusion, and Helion Energy, who is focusing on D-He3 fusion with pulsed compression. Helion forms two D-He3 FRC plasma rings at either end of an hourglass shaped chamber. They then use magnetic fields to accelerate the FRCs to a million miles an hour so that they collide at the neck of the hourglass, achieving fusion (the device is pictured below). Their 7th generation Polaris fusion prototype achieved a 150 million degrees Celsius plasma temperature to demonstrate D-T fusion as a stepping stone to D-He3 fusion. Helion, which was founded in 2013, has raised slightly over $1B so far towards their approach.
TAE Technologies, which was founded in 1998 and raised roughly $1.3 billion before pursuing a special purpose acquisition company (SPAC) merger with Trump Media, is taking a slightly different approach. TAE utilizes neutral beam injection to provide the spin which creates the ring, and stabilizes the plasma. TAE’s latest device, which is called “Norm” and is pictured below, has been running since 2025. In this picture, the plasma is contained between the eight neutral beam injectors shown sticking out of the center of the device, which forms a stable single plasma ring between them. Their next generation machine, code name Copernicus, is expected to demonstrate net energy generation. It will be followed by DaVinci, TAE’s prototype power plant in the early 2030s.
Magnetic Mirrors: A Plasma Trap
Like tokamaks, stellarators, and z-pinch machines, magnetic mirrors were one of the earliest approaches explored in the 1950s for achieving fusion. Many different prototype fusion magnetic mirrors were tried out between the 1960s, 1970s, 1980s, and 1990s. One of the most successful prototypes of these was the Wisconsin HTS Asymmetric Mirror (WHAM), a next-generation fusion experiment that achieved a world record 17-tesla magnetic field. WHAM, which is being co-designed by UW-Madison,
Commonwealth Fusion Systems, and Realta Fusion, utilizes a magnetic mirror variant called ‘vortex confinement’ to prevent plasma from hitting the walls. It utilized a 1 MW/25 keV neutral beam and a 0.9 MW/110 GHz electron-cyclotron heating system to heat the hydrogen atoms into a plasma. Even larger prototypes such as Anvil and Hammer, which will attempt to demonstrate net positive energy production and commercial viability, will be built by Realta Fusion, with magnets provided by CFS.
Conclusion: Magnetic Confinement has Many Flavors
Between this article and the previous article, The Fusion Report explored at least five different flavors of magnetic confinement fusion out there under development by industry for use in commercial fusion applications. Interestingly, this does not count other new variants in development in universities and other research institutions. This is unsurprising given that magnetic confinement fusion has been around for over 75 years. This is actually a positive because it means more shots on goal. Speaking of goals, we’ll use our final article to summarize who makes the award podium – stay tuned!
