The unique capabilities of the SPARC tokamak mean that it has the potential to contribute significantly to tokamak science and plasma physics, motivating further collaboration and broader data access beyond the CFS and MIT teams. SPARC is a compact, high-field tokamak that is currently under construction and is predicted to achieve burning plasma conditions once in operation. SPARC experimental data has the potential to advance the understanding of many aspects of tokamak physics, including but not limited to confinement and stability at high field and high density, burning plasma physics, disruption physics, and boundary physics and heat flux management in power plant-relevant conditions. The SPARC team is already a combination of members from Commonwealth Fusion Systems (CFS), a privately funded company, and the Massachusetts Institute of Technology (MIT), a non-profit university. This article describes the opportunities for the SPARC team to work with other researchers to advance toward a fusion power plant on the fastest possible time scales and to simultaneously broaden scientific understanding of plasma physics, meeting the missions of both CFS and academic partners.

The past ten years, and the past five in particular, have seen a significant shift in the fusion research landscape, with increases in private funding so large that they now match or exceed public funding in many places.1 These privately funded ventures are aimed toward commercializing fusion power and so are targeted in their research interest: resources are dedicated to gaining information that directly leads to a fusion power plant or components thereof. Publicly funded research, however, in many cases has the larger goal of advancing the frontiers of human knowledge and supporting education in addition to solving the specific challenges of fusion power.

While these missions are different, in many cases they overlap. The research performed in the public sector over the past 70 years has brought fusion energy science and technology to the point where near-term commercialization is possible. Without the past achievements of the worldwide fusion research program, it is very unlikely any private companies would be where they are today. This is certainly true for Commonwealth Fusion Systems (CFS), whose SPARC tokamak design2 is based on the extensive physics knowledge gathered over the decades and recently refined for the design of ITER.3 It is also squarely in the interest of CFS and many other fusion companies for the public program to continue advancing the understanding of tokamak science in the future.

This overlap in mission also applies in the other direction. While the primary mission of the SPARC tokamak is to demonstrate Q > 1 (scientific breakeven)4 and to set the stage for construction of the ARC power plant (early iterations of which are discussed in Refs. 5 and 6), the SPARC project has and will continue to learn new physics along the way. The SPARC team has from the beginning emphasized the importance of making its scientific results available to the broader physics community, publishing an initial series of seven papers in the Journal of Plasma Physics describing the physics basis for SPARC,2,7–13 continuing to publish subsequent scientific results in other journals,14–18 and presenting at conferences and seminars. CFS has also made some physics calculation results and codes publicly available on GitHub for any that wish to pursue their own studies.19 

Together, public and private sector research efforts have the potential to mutually benefit one another. Tightly focused private research will push the field in very applied directions, benefitting from and continuing to contribute back to publicly funded work. This overlap in mission and the benefit of public and private fusion programs working together has been clear from the very beginning of the SPARC project, which originated as a joint project between CFS and the Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center (PSFC).20 The deep expertise and ability to do exploratory physics work at MIT complements the speed and tightly focused nature of a company like CFS. While there are occasionally different priorities that necessitate reconciliation, the partnership is mutually beneficial and has enabled the SPARC project to start at scale and move rapidly.

While all of the scientific work so far on SPARC has been predictive and used in the design of the tokamak and plant, the machine is now under construction and will soon start producing experimental data. As a part of the CFS belief that open science is the most effective way to advance the understanding of fusion, the intent is to publish physics results from SPARC once they are available. CFS will continue to work in close collaboration with academic, US Department of Energy National Laboratory, and international laboratory partners, building on the success of the past five years and contributing to the missions of both types of organizations.

This article focuses primarily on the potential of SPARC to contribute as a part of a joint public–private scientific program. The SPARC tokamak is unique compared to any publicly funded research device today and has the potential to contribute significantly to the worldwide understanding of tokamak physics. The rest of the article is organized as follows. Section II describes the SPARC tokamak and features of the tokamak and plant that make it attractive as a research facility. Section III describes the access SPARC will provide to unique plasma parameter ranges and the research potential in these areas. Section IV describes possible modes of collaboration between the SPARC team and the publicly funded program, including the present intent for SPARC data access policies. Section V summarizes these points as well as discussing possible next steps to further integrate SPARC physics into the publicly funded physics program.

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