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Commonwealth Fusion Systems

Senior Scientist - ARC Plasma Instrumentation

Join Commonwealth Fusion Systems in Devens, Massachusetts as a Senior Scientist - ARC Plasma Instrumentation. Lead plasma measurement design for fusion power plants, collaborate with R&D, and help develop innovative diagnostics. Enjoy competitive pay, equity, flexible vacation, and strong benefits in a mission-driven team.
Commonwealth Fusion Systems
Commonwealth Fusion Systems
Devens, Massachusetts, United States Hybrid Full time USD 110k–185k yearly UTC-05:00

Commonwealth Fusion Systems

Company Overview

Commonwealth Fusion Systems (CFS)

Cambridge, MA, United States

2018

Approximately 430 employees (source: zoominfo.com). Revenue figures vary, with reports indicating $211.3 million or $31.7 million, though as a pre-revenue fusion developer focused on R&D, these may reflect funding or operations rather than sales.

What They Do

Commonwealth Fusion Systems (CFS) is a pioneering private fusion energy company that specializes in tokamak-based magnetic confinement fusion. Founded as a spinout from MIT's Plasma Science and Fusion Center, CFS focuses on utilizing high-temperature superconducting magnets to achieve commercial net energy production (source: cfs.energy). The company has made significant strides in its technology, particularly with the development of compact fusion machines that leverage decades of tokamak science. Their flagship projects, SPARC and ARC, aim to demonstrate net energy gain and commercial viability in the coming years (source: cfs.energy).

Projects & Track Record

CFS is currently engaged in several groundbreaking projects, most notably the construction of SPARC, which is set to be the world's first net-energy fusion machine. Located at their Fusion Energy Campus in Devens, Massachusetts, SPARC aims to demonstrate net energy gain by the late 2020s (source: cfs.energy). Additionally, CFS is planning the ARC project, a 400 MW-class grid-scale tokamak power plant designed for commercial deployment in the early 2030s. These projects are underpinned by significant technological advancements, including the successful testing of the central solenoid magnet module (CSMC) in November 2024, which confirmed the manufacturability of critical components for SPARC (source: zoominfo.com).

Recent Developments

In the past two years, CFS has made remarkable progress, including the opening of its Devens Fusion Energy Campus on February 10, 2023, which was attended by notable figures such as U.S. Secretary of Energy Jennifer Granholm (source: cfs.energy). The company has also secured substantial funding, raising $863 million in August 2024, building on a previous $1.8 billion round in May 2023, bringing total funding to over $2 billion (source: wbjournal.com). Furthermore, CFS announced its first commercial power plant site in Chesterfield County, Virginia, which will be independently financed and operated, with plans for grid connection in the early 2030s (source: zoominfo.com).

Working There

CFS offers a range of roles across various disciplines, including fusion science, engineering, manufacturing, and materials science. The majority of their workforce is based at the Devens campus, which has grown to over 430 employees (source: cfs.energy). The company culture emphasizes rapid execution and transparency, attracting top talent from the fusion and manufacturing sectors. Key executives include Co-Founder and CEO Bob Mumgaard, along with other leaders in operations and science, indicating a strong demand for expertise in tough tech and physics (source: nasdaqprivatemarket.com). While specific benefits are not detailed, the scale-up and investor backing suggest competitive packages for high-caliber roles in a mission-driven environment (source: cfs.energy). Job seekers are encouraged to monitor their careers page for openings related to SPARC and ARC advancements.


Last updated on 2026-02-23 | Report an issue

Job Description

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 and suppliers to build the energy industry of the future.

We're in the best position to make it happen. Since 2018, we've raised nearly $3 billion in capital, making us the largest and leading private 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 Senior Scientist - ARC Plasma Instrumentation

Commonwealth Fusion Systems is currently in the early stages of designing the ARC fusion power plant. The tokamak will share some attributes with SPARC but will also present many new challenges, especially in the thermal and radiological environment inside of the tokamak. The Senior Scientist, ARC Plasma Instrumentation will lead early efforts at scoping out necessary measurements in the plasma for plant control and the technologies that will be used to make these measurements. The Senior Scientist will build off what has been done for SPARC, with a particular focus on determining the minimum necessary set of measurements and instruments for a power plant. In many cases, novel techniques may be required in order to operate in the thermal and radiological environment, so the scientist will work closely with R&D teams to determine necessary R&D for this instrumentation. CFS is looking for someone with experience designing, building, and operating fusion diagnostics and with an interest in exploring a breadth of measurements and technologies for future power plants.

What you'll do

  • Determine and continually refine the set of measurements necessary to operate the ARC tokamak, coordinating with the plasma control and plasma physics teams
  • Evaluate potential techniques and technologies to make the measurements required in ARC, with a particular focus on techniques that will work robustly in the thermal and radiological environment in ARC
  • Determine which techniques and technologies will require significant R&D and work with CFS R&D teams to scope out what projects are necessary to develop these technologies
  • Develop early concepts, layouts, and requirements for proposed plasma instrumentation on ARC, including space requirements both inside and outside of the tokamak
  • Work with the remote maintenance team to ideate and evaluate remote replacement strategies for plasma instrumentation
  • Longer term, coordinate efforts of various engineering disciplines to design and analyze instrumentation concepts
  • Coordinate efforts of external collaborators on ARC plasma instrumentation

What we're looking for

  • PhD in experimental plasma physics or a closely related field
  • 5+ years experience (post degree) in plasma physics or fusion research
  • Experience designing, building, and operating plasma instrumentation (diagnostics) in plasma experiments
  • Experience working on a multi-disciplinary engineering project
  • Experience performing independent research
  • Knowledge of plasma instrumentation (diagnostics) on tokamaks or similar fusion experiments
  • Knowledge of engineering sufficient to interact with multi-disciplinary engineering teams
  • A desire to design commercial fusion products
  • Ability to adapt to a rapidly changing environment
  • Ability to work with collaborations from a variety of academic institutions

Bonus points for

  • Experience with Python

Must-have Requirements

  • Perform activities such as typing or sitting for extended periods of time
  • Willingness to travel or work required nights/weekends/on-call regularly
  • Work in a facility that contains industrial hazards including heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics

$110,000 - $185,000 a year

Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:

  • Competitive compensation with equity
  • 13 Company-wide Holidays
  • Flexible vacation days
  • 10 sick days
  • Generous parental leave policy
  • Health, dental, and vision insurance
  • 401(k) with employer matching
  • Professional growth opportunities
  • Team-building activities

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.

Apply now

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About the role

March 8, 2026

Full time

Company

March 8, 2026

Hybrid

USD 110k–185k yearly

Solar Energy , Wind Energy , Hydropower , Bioenergy , Energy Storage , Tidal and Wave Energy , Geothermal Energy , Hydrogen

Commonwealth Fusion Systems

cfs.energy

  •  Devens, Massachusetts, United States

5+ years in plasma physics or fusion research

UTC-05:00