Principal Experimental Scientist

About Helion We are a fusion power company based in Everett, WA, with the mission to build the world's first fusion power plant, enabling a future with unlimited clean electricity. Our vision is a world with clean, reliable, and affordable energy for everyone. Since Helion's founding in 2013, we have raised over $1 billion from long-time investors such as Sam Altman, Mithril, and Capricorn Investment Group as well as new investors SoftBank and Lightspeed to propel us forward. Our last prototype, Trenta, completed 10,000 high-power pulses and reached plasma temperatures of 100 million degrees Celsius (9 keV). We are now operating Polaris, our next prototype on the path to the world's first fusion power plant. This is a pivotal time to join Helion. You will tackle real-world challenges with a team that prizes urgency, rigor, ownership, and a commitment to delivering hard truths – values essential to achieving what no one has before. Together, we will change the future of energy, because the world can't wait. What You Will Be Doing: We are looking for a Principal Experimental Plasma Scientist to lead the plasma diagnostic effort of Helion's fusion generators. This is an onsite role that reports directly to our Director of Plasma and Nuclear Science at our Everett, WA office. You Will: - Own the end-to-end design and deployment of a comprehensive suite of plasma diagnostics, collaborating closely with physicists, engineers, designers, and data analysts to ensure robust, scalable instrumentation that meets both experimental and operational requirements - Integrate cross-disciplinary technical input from experts across Helion—including plasma physics, machine operations, controls, and data science—to align diagnostic capabilities with real-time operational needs and long-term scientific milestones - Lead the hands-on execution of assembly, installation, calibration, and commissioning processes for diagnostics across multiple campaigns and testbeds. Ensure high data fidelity through rigorous validation and alignment procedures - Develop foundational expertise in pre-ionization plasma diagnostics, establishing best practices and internal methodologies that inform next-generation fusion device development optimized for energy gain and power conversion - Analyze diagnostic data in real time to extract actionable insights about plasma behavior, inform operational tuning, and identify opportunities for performance optimization and system redesign - Partners with leadership across the organization, contributing to strategic planning, roadmap development, and long-term technical vision Required Skills: - Ph.D. in physics, electrical engineering, aerospace engineering, or a related discipline, with a focus on plasma science, diagnostics, or high-vacuum instrumentation - 10+ years of experience working in advanced laboratory environments, with extensive hands-on work involving plasma generation, plasma systems, and UHV vacuum infrastructure - Demonstrated track record using diagnostic measurements (e.g., interferometry, spectroscopy, Langmuir probes, magnetic coils, electrostatic diagnostics) to evaluate plasma parameters such as density, temperature, and current profiles, directly influencing system improvements - Deep expertise and unique domain knowledge in multiple areas of plasma diagnostics and fusion engineering. Recognized as a subject matter expert who operates independently Benefits Our total compensation package includes benefits, including but not limited to: • Medical, Dental, and Vision plans for employees and their families • 31 Days of PTO (21 vacation days and 10 sick days) • 10 Paid holidays, plus company-wide winter break • Up to 5% employer 401(k) match • Short term disability, long term disability, and life insurance • Paid parental leave and support (up to 16 weeks) • Annual wellness stipend Helion is an equal opportunity employer and value diversity at our company. We do not discriminate based on race, religion, color,