Realta Fusion Demonstrates Direct Plasma-Energy Conversion on WHAM Device

Realta Fusion and the University of Wisconsin–Madison have demonstrated direct energy conversion on the Wisconsin HTS Axisymmetric Mirror prototype, marking the first reported application of the technology to a fusion plasma by a private fusion company. The system converts part of the kinetic energy carried by charged particles escaping from the magnetic mirror directly into electrical current, reducing the amount of plasma energy that must pass through a conventional thermal cycle.

The prototype converter uses three fine-mesh grids consisting of a grounded stage, an electron-repulsion grid and an ion-collection grid. An electrostatic potential slows charged particles leaving the mirror’s loss cone and captures their energy as electricity. During WHAM plasma operations, the system produced multiple amperes at approximately 100 volts, sufficient for a small proof-of-concept electrical load. The experiment used deuterium plasma, meaning most of the recovered energy originated from externally supplied plasma-heating power rather than fusion-generated alpha particles.

Realta plans to scale the technology from its present demonstration level to multi-kilowatt and eventually multi-megawatt systems. In future deuterium-tritium magnetic-mirror power plants, direct conversion could recover energy from charged fusion products and recirculating heating systems more efficiently than a thermal cycle, potentially lowering the fusion gain required for net-electric operation. The architecture may also support advanced fuel cycles such as catalysed deuterium-deuterium and deuterium-helium-3, although the company emphasised that the WHAM test did not demonstrate net-electricity production or large-scale conversion of fusion-born energy.