Intern - Plasma Physics - Summer 2027

Commonwealth Fusion Systems LLC; Harvard (MA); On-site; USD 34,000 - 52,000; Full time

Benefits offered by this job

Sick time

Health Insurance

401(k) matching

Growth opportunities

Team activities

Job summary

Commonwealth Fusion Systems is seeking a Plasma Physics Intern to join the plasma digital twin team for 2027. The internship is 13–18 weeks, 40–50 hours per week, on-site in Devens, MA, with pay based on year in school.

Interns will tackle 1–2 projects, with opportunities in AI/physics intersections. Open to undergrad and graduate students across plasma physics, AI, and related fields, with travel and on-call duties as needed.

Qualifications

• Pursuing an engineering degree with focus in plasma physics or a related field (engineering, computer science, etc.).
• Introductory knowledge of plasma physics, tokamaks and magnetic confinement fusion.
• Experience using agentic AI tools for coding and research.

Responsibilities

• Perform plasma physics calculations for SPARC and/or ARC using models or data.
• Develop computational modules for the SPARC digital twin, including physics and engineering models.
• Develop AI workflows to accelerate complex physics calculations using surrogate models.
• Develop data visualization methods to display plasma physics data inside the digital twin.

Skills

Python

C++

Git

Agentic AI (Claude, ChatGPT)

Plasma physics knowledge

Technical writing

Education

Engineering degree

Job description

About Commonwealth Fusion Systems:

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 Plasma Physics Intern

The plasma physics department at CFS is looking for a summer intern to join the plasma digital twin team for 2027. We encourage both undergraduate and graduate applicants, as this internship will be tuned to match the candidate’s current skill set and education level. This internship will consist of 1-2 projects, selected from several potential project options by the intern at the onset of the internship. Given the recent advancements with LLMs and agentic AI, projects that address questions at the intersection of AI and physics are likely. Students studying all branches of plasma physics are encouraged to apply, as well as students with backgrounds applying machine learning or AI to physics problems.

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:

Responsibilities could include any combination of the following:

• Perform plasma physics calculations for SPARC and/or ARC, using computational models or experimental datasets
• Develop new computational modules that will be used in the SPARC digital twin (a computational model of SPARC plasmas and machine components), including physics and engineering models
• Develop AI workflows to accelerate complex physics calculations using surrogate models
• Develop data visualization methods to display complex plasma physics data inside the digital twin

What we’re looking for:

• Pursuing an engineering degree with focus in the field of in plasma physics, or a related field (engineering, computer science, etc.)
• Introductory knowledge of plasma physics, specifically tokamaks and magnetic confinement fusion
• Knowledge of using agentic AI (Claude, ChatGPT, etc.) for coding and scientific research
• Experience with Python, C++, or similar
• Version control with git or similar
• Excellent writing and technical communication 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

$25 - $38 an hour

Rates are aligned to your current year in school, ensuring equitable and consistent pay across our intern program.

For BS interns, the hourly rate is $25–$32

F or MS/PhD interns, the rate is $35–$38

Benefits included for full-time interns:

• 40 hours of sick time
• Health, dental, and vision insurance
• 401(k) with employer matching (must be 21 years of age to enroll)
• Professional growth opportunities
• Team-building activities

#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.