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Commonwealth Fusion Systems

Scientist - Scenarios and Integrated Modeling

Become a Scientist - Scenarios and Integrated Modeling at Commonwealth Fusion Systems in Devens, Massachusetts. This role involves developing plasma physics scenarios for SPARC and ARC through integrated simulation and modeling. Enjoy competitive compensation, flexible vacation days, and opportunities for professional growth.
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.

Contact


Last updated on 2026-01-02 | Report an issue

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 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 Scientist - Scenarios and Integrated Modeling

Scientist - Scenarios and Integrated Modeling will develop plasma physics scenarios for SPARC and ARC based on comprehensive integrated simulation and modeling of the core and edge plasma. Will coordinate with a multi-institutional team of plasma physics experts to develop and improve an integrated modeling toolset, and to employ that toolset for experimental planning and analysis on SPARC.

Commonwealth Fusion Systems is assembling the high-field SPARC tokamak, which aims to be the first magnetic fusion device to achieve net fusion energy, and is predicted to be able to achieve high gain and fusion power up to 140MW. In parallel CFS is designing and optimizing the ARC fusion power plant, the first of which will be built in Virginia in the early 2030s. To achieve SPARC's goals and validate the physics understanding necessary for optimizing ARC, we plan to develop and continuously improve a comprehensive predictive toolchain, including all physics capabilities needed to evaluate plasma scenario performance and robustness. The person in this role will coordinate and contribute to the development and testing of this toolchain, and its use in planning and executing experiments on SPARC, as well as in development and optimization of future power plants. The person in this role will also play a key role in defining plasma operation goals, identify optimal operation scenarios for each goal, and participate directly in execution and analysis of SPARC operations.

What you'll do

  • Refine, optimize, and validate a comprehensive integrated modeling toolset capable of predicting plasma performance and dynamics
  • ??? Toolset will include models of: core turbulent and neoclassical transport, H-mode pedestal and L-mode edge, coupling to boundary, ICRH heating, energetic particle physics, MHD stability, and impurity transport
  • ??? Toolset will include very rapid execution workflows appropriate for control, rapid execution workflows appropriate for experiment planning and optimization, as well as higher fidelity models for offline analysis and deeper exploration of critical physics
  • Work closely with a multi-institutional team of experts to incorporate state-of-the-art physics capabilities, and validate models
  • Employ integrated modeling tools to plan and execute plasma pulses to achieve key goals including net fusion power on SPARC, and continuously improve toolset as new data becomes available
  • Identify, execute, and continuously improve operational scenario for achieving SPARC goals
  • Work closely with physics, diagnostics, operations, plasma control, and software teams to design and execute plasma scenarios on SPARC
  • Contribute to physics design and optimization of ARC

What we're looking for

  • PhD in plasma physics or a closely related discipline
  • Minimum 2 years post-PhD experience in magnetic fusion
  • Significant experience with fusion plasma simulation and modeling software
  • Significant experience in planning, executing, and/or analyzing fusion experiments
  • Expertise in magnetic fusion experiment and simulation
  • Strong insight on physics issues associated with integration of regions (core, edge, boundary) and physics (transport, MHD, heating, plasma material interaction..) in magnetic fusion systems
  • Strong teamwork skills
  • Ability to communicate ideas and results clearly
  • Results focused with understanding of the fusion goal
  • Ability to think clearly and perform well under pressure

Bonus points for

  • 5+ years post-PhD experience, including hands-on experience planning and executing magnetic fusion experiments, and experience using and developing fusion simulation codes
  • Fusion experiment planning and control room experience
  • Familiarity with tokamak simulation tools including core transport models, pedestal/edge models, boundary models
  • Experience with plasma transport codes such as TRANSP, IPS-FASTRAN, ASTRA, JINTRAC, TGYRO.
  • Familiarity with ICRF physics and operation
  • Familiarity with MHD physics, and impact of non-axisymmetric fields
  • Familiarity with tokamak plasma breakdown, rampup and rampdown
  • Experience developing fusion simulation codes
  • Experience integrating simulation tools into a robust toolchain
  • Familiarity with Python, C++, Fortran, and git version control
  • Experience with broad based fusion collaborations, ideally including international collaborations

Must-have Requirements

  • Perform extended activities such as typing, standing, sitting, etc.
  • 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
  • 12.5 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.

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About the role

November 26, 2025

Full Time

Company

January 2, 2026

Hybrid

USD 110k–185k yearly

Commonwealth Fusion Systems

cfs.energy

  •  Devens, Massachusetts, United States

Minimum 2 years post-PhD experience

UTC-05:00

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