A University of Wisconsin-Madison spinoff developing high-field mirror machines for near-term industrial heat and clean energy, leveraging high-temperature superconducting magnets to revive and modernize the mirror concept.
Realta Fusion was founded in 2022 as a spinoff from the University of Wisconsin-Madison, where mirror-machine physics has been studied for decades. The company's co-founders include Cary Forest, a plasma physicist whose Wisconsin HTS Axisymmetric Mirror (WHAM) experiment forms the scientific basis for Realta's commercial pathway. The company's name derives from the Irish word réalta, meaning star.1
Realta's strategy is distinctive in the fusion startup landscape: rather than targeting electricity generation as a first product, the company aims to deliver high-temperature industrial process heat — a market that accounts for roughly 10% of U.S. energy consumption and is extremely difficult to decarbonize with renewables alone.
The mirror machine is one of the oldest magnetic-confinement concepts, first explored in the 1950s. Plasma is confined in a linear magnetic bottle between two regions of high magnetic field ("mirrors") that reflect charged particles back toward the center. The concept fell out of favor in the 1980s after the MFTF-B mirror at Lawrence Livermore was completed but never operated, a casualty of budget politics rather than physics failure.3
Realta's innovation is the application of modern high-temperature superconducting (HTS) magnets to the mirror geometry. HTS magnets, built from rare-earth barium copper oxide (REBCO) tape, can produce far stronger fields than the copper or low-temperature superconducting magnets available in the 1980s. Higher mirror-field ratios improve confinement, and the compact coils reduce machine size and cost.
The WHAM experiment at Wisconsin is the proof-of-concept device. WHAM uses a 17-tesla HTS mirror coil — among the strongest ever applied to a fusion plasma experiment — and is designed to confine a deuterium plasma heated by neutral-beam injection. Early results have demonstrated plasma confinement consistent with theoretical predictions for the improved mirror ratio.4
Realta's near-term business case does not require a mirror machine to reach breakeven fusion energy (Q ≥ 1). Instead, the company envisions a Q < 1 device that produces copious fast neutrons, whose kinetic energy is captured as heat in a surrounding blanket. Even with Q below unity, the thermal output can serve industrial customers who currently burn natural gas at very high temperatures — cement kilns, steel furnaces, chemical plants — if the economics of the neutron source compete with fossil fuel.
The longer-term roadmap includes scaling the mirror to Q > 1 and adding electricity generation, but the industrial-heat-first approach gives Realta a potential revenue stream well before a full power plant is built. This staged commercialization model distinguishes Realta from most fusion companies that target the grid as their first customer.