Senior Experimental Scientist

Senior 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: Helion is hiring an Experimental Scientist to own the development of Helion’s RF pre-ionization capability for our FRC system. In this role, you will develop, optimize, and validate a high-performance RF plasma source to achieve targeted plasma density, stability, and coupling efficiency. You will lead hands-on experimental work spanning RF hardware, antenna/coupling design, diagnostics, and operational procedures to deliver repeatable plasma startup. You will work closely with plasma physics, pulsed power, mechanical, controls, and operations teams to ensure the source performs reliably in the full system environment. This is a highly experimental, iteration-driven role where you will use data to diagnose issues, drive design changes, and rapidly validate improvements. This is an onsite role based in Everett, WA and reports to the Director of Experimental Science. You Will: - Develop, optimize, and validate a RF plasma source for pre-ionization, integrated with Helion’s FRC system - Design and iterate RF-facing hardware (e.g., antenna geometry, coupling structures, matching approach) to improve density, stability, and coupling efficiency - Plan and execute experimental campaigns, including parameter scans, acceptance tests, and performance benchmarking against defined targets - Build and refine diagnostics and analysis methods to quantify plasma formation, density evolution, stability, and RF coupling performance - Partner with cross-functional teams (pulsed power, controls, mechanical, operations) to integrate, commission, and operate the system safely and reliably - Communicate progress through clear technical documentation and regular updates, including risks, tradeoffs, and next-step recommendations Required Skills: - Ph.D. in plasma physics, applied physics, electrical engineering, or related discipline with a strong experimental focus - Hands-on experience developing and troubleshooting RF plasma sources (ICP, CCP, helicon or similar acceptable) - Demonstrated ability to design, execute, and iterate on experimental hardware in a fast-paced R&D environment - Strong understanding of RF coupling concepts and the practical realities of integrating RF systems into complex machines - Proficiency with experimental data analysis (diagnostics interpretation, parameter sweeps, uncertainty-aware decision making) - Track record of cross-functional collaboration and technical ownership from concept through integration, testing, and validation 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 ... (truncated, view full listing at source)