Intern - Scientific Software Engineer - Summer 2027

Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy. Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future. We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world. Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team. If that’s you and this role fits, we want to hear from you. Join the power movement as a Scientific Software Engineering Intern We are looking for a talented Scientific Software Engineering Intern to join our team! CFS interns are highly valued within the organization and placed into meaningful and challenging roles.

Program Details: • 13-18 week internship • 40-50 hours per week with set hourly salary based on year in school • Opportunities on site in Devens, MA. If an intern is going to be on site, you will be responsible for your own transportation and housing • Specific project assignments and required technical skillset will vary based on the team’s existing need. • Opportunities available for currently enrolled college students in all levels of schooling from bachelor’s degree to PhD • Interns must be authorized to work in the United States for any employer

What you'll do: • Port high-performance electromagnetics kernels to the GPU. You’ll start with the Biot-Savart magnetic-field calculation in cfsem, CFS’s open-source Rust library, and extend it to include cross-platform GPU kernel variants with Python bindings • Hold your code to a scientific-correctness bar. You’ll check the GPU kernels against cfsem’s existing unit tests and CPU versions, and determine if your methods are accurate enough for engineers who rely on the results to design superconducting magnets • Measure and report GPU performance. You’ll benchmark speed and accuracy against the optimized multithreaded Rust CPU kernels, and present a clear recommendation on where GPU acceleration pays off and where it doesn’t • Ship public open-source work. You’ll put the new kernels behind cfsem’s existing Python interface so they reach CFS engineers working on SPARC and future fusion magnets, and you’ll leave with merged contributions to a public Rust/Python project

What we’re looking for: • Pursuing an engineering degree with focus in the field of Computer Science • Contributed to a multi-person software project • Rust programming language • Software performance engineering (class, project or internship experience) • Demonstration of exceptional results through a range of different pursuits • High self-motivation and drive to execute quickly with excellent troubleshooting/problem-solving skills

Must-have Requirements: • Willingness to travel or work required nights/weekends/on-call occasionally • Perform activities such as typing, standing, or sitting for extended periods of time • Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, and cryogenics

#LI-Onsite At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges. We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law. This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.