Periodic Reporting for period 1 - CSFPP (Current-free Stellarator for Fusion Power Plants)
Berichtszeitraum: 2024-08-01 bis 2025-07-31
Fusion energy is emerging as a powerful answer to our world’s growing need for clean, reliable, and scalable energy. As climate change accelerates and technology developments such as AI drive up electricity demand, there is a growing urgency to find solutions that go beyond intermittent solar and wind. Fusion, which mimics the energy-generating process that powers the sun, promises abundant, safe and clean energy —without producing carbon emissions or long-lasting nuclear waste. Proxima Fusion is focusing on the clearest and most robust path to commercial fusion energy: quasi-isodynamic (QI) stellarators. Spun out from the Max Planck Institute for Plasma Physics (IPP) in 2023, Proxima is building on the groundbreaking results of IPPs Wendelstein 7-X experiment, the world’s most advanced stellarator (located in Greifwald, Germany).
Historically, the leading path toward fusion has focused on devices called tokamaks. While promising, tokamaks come with serious hurdles, such as instability in the plasma and the need for constant, complex control. Thanks to major advances in superconducting materials and computational design tools, as well as significant evidence from W7-X, stellarator design is now able to overcome the challenges of tokamaks. The current challenge is primarily one of engineering integration—bringing these components together into a system that can operate reliably at scale.
Proxima is using a simulation-driven approach to designing and building stellarator fusion power plants that leverage advanced optimization methods and computing power, resulting in high speed iteration work at low cost. Proxima is building a world-class team of engineers, physicists and operators for large scale infrastructure, and closing partnerships with industry leaders and the IPP in order to build - first - a proof of concept stellarator demonstrator (called Alpha) by 2031, followed closely by a commercial fusion plant within the mid-to-late 2030s.
The CSFPP (current-free stellarator fusion power plant) project aims to support the development of the demonstrator stellarator, Alpha, as well as Proximas commercial roadmap. The successful deployment of Alpha will de-risk fusion technologies and enable critical fusion industry growth in Europe.
Historically, the leading path toward fusion has focused on devices called tokamaks. While promising, tokamaks come with serious hurdles, such as instability in the plasma and the need for constant, complex control. Thanks to major advances in superconducting materials and computational design tools, as well as significant evidence from W7-X, stellarator design is now able to overcome the challenges of tokamaks. The current challenge is primarily one of engineering integration—bringing these components together into a system that can operate reliably at scale.
Proxima is using a simulation-driven approach to designing and building stellarator fusion power plants that leverage advanced optimization methods and computing power, resulting in high speed iteration work at low cost. Proxima is building a world-class team of engineers, physicists and operators for large scale infrastructure, and closing partnerships with industry leaders and the IPP in order to build - first - a proof of concept stellarator demonstrator (called Alpha) by 2031, followed closely by a commercial fusion plant within the mid-to-late 2030s.
The CSFPP (current-free stellarator fusion power plant) project aims to support the development of the demonstrator stellarator, Alpha, as well as Proximas commercial roadmap. The successful deployment of Alpha will de-risk fusion technologies and enable critical fusion industry growth in Europe.
Proxima has evolved the preliminary concept design of legacy stellarators such as W7-X into a detailed design and engineering architecture in order to create a common language with which to develop, optimize and analyse fusion power plants (WP3). The resulting system design model comprises a plant breakdown structure (PBS) and system requirements map, detailing key process descriptions and interfaces. The design architecture provides a reference framework within which stellarator configurations are mapped.
Proxima has created an industry-leading simulation and optimization framework called Starfinder. This tool allows for optimization and analysis of stellarator configurations (WP4) and supports a range of different use cases. The functionality includes but is not limited to:
● Optimization of stellarators for custom target functions
● Use of multi-fidelity models to support a variety of use cases, ranging from scoping studies to parametric CAD.
● Visualization of stellarators and respective optimization runs
● Standardised results and analysis of results that are stored in a database
● Interfaces to common engineering codes and electromagnetic simulation codes
● Analysis including but not limited to MHD stability, fast particle confinement, bootstrap current, geometrical distances and clearances, plasma profile predictions, neutronic peak wall loads and thermal stresses in the first wall.
Based on outputs from Starfinder, we are improving candidate configurations for our demonstrator, Alpha. By interfacing with generic Stellarator models, Proxima has been able to simulate all major subsystems for a stellarator, allowing a comprehensive mapping of engineering and physics tradeoffs in stellarator design.
The first internal design review for the Alpha stellarator, the demonstrator that is a key milestone on the way to a commercial fusion power plant, was held in July 2025.
Proxima has created an industry-leading simulation and optimization framework called Starfinder. This tool allows for optimization and analysis of stellarator configurations (WP4) and supports a range of different use cases. The functionality includes but is not limited to:
● Optimization of stellarators for custom target functions
● Use of multi-fidelity models to support a variety of use cases, ranging from scoping studies to parametric CAD.
● Visualization of stellarators and respective optimization runs
● Standardised results and analysis of results that are stored in a database
● Interfaces to common engineering codes and electromagnetic simulation codes
● Analysis including but not limited to MHD stability, fast particle confinement, bootstrap current, geometrical distances and clearances, plasma profile predictions, neutronic peak wall loads and thermal stresses in the first wall.
Based on outputs from Starfinder, we are improving candidate configurations for our demonstrator, Alpha. By interfacing with generic Stellarator models, Proxima has been able to simulate all major subsystems for a stellarator, allowing a comprehensive mapping of engineering and physics tradeoffs in stellarator design.
The first internal design review for the Alpha stellarator, the demonstrator that is a key milestone on the way to a commercial fusion power plant, was held in July 2025.
Proxima has leveraged computational tools to reduce the effort and level of investment required for stellarator design optimization beyond the state of the art. Stellarator design optimization has a high complexity cost which is eased through Starfinder - allowing for faster analysis and iteration. The Starfinder framework connects physics and engineering outputs, enabling coordinated design development that has expanded the understanding of tradeoffs between engineering and physics aspects in stellarators. These developments have allowed Proxima to rapidly evolve the systems architecture and requirements for the Alpha demonstrator, resulting in cost reduction that is applicable to the short-term design horizon and the long-term implementation horizon for fusion power plants.
In May 2025, Proxima published Stellaris: A high-field quasi-isodynamic stellarator for a prototypical fusion power plant in Fusion Engineering and Design (https://doi.org/10.1016/j.fusengdes.2025.114868(öffnet in neuem Fenster)). Stellaris, the first stellarator-based fusion power plant, is the result of a public-private partnership between Proxima Fusion engineers and IPP scientists. It is the first time that a high consistency modular coil QI stellarator power plant conceptual design has been published, bringing together co-authors from different institutions to work collaboratively on one paper, a strong indicator for the strength of the European fusion industry.
This is complemented by the August 2025 announcement of a partnership between Proxima and Fusion for Energy, the EU organization managing Europe’s contribution to the ITER project. This partnership will allow space for discussing and developing the fusion space - from supply chains to neutronics code.
In May 2025, Proxima published Stellaris: A high-field quasi-isodynamic stellarator for a prototypical fusion power plant in Fusion Engineering and Design (https://doi.org/10.1016/j.fusengdes.2025.114868(öffnet in neuem Fenster)). Stellaris, the first stellarator-based fusion power plant, is the result of a public-private partnership between Proxima Fusion engineers and IPP scientists. It is the first time that a high consistency modular coil QI stellarator power plant conceptual design has been published, bringing together co-authors from different institutions to work collaboratively on one paper, a strong indicator for the strength of the European fusion industry.
This is complemented by the August 2025 announcement of a partnership between Proxima and Fusion for Energy, the EU organization managing Europe’s contribution to the ITER project. This partnership will allow space for discussing and developing the fusion space - from supply chains to neutronics code.