Principal Electrical Engineer - RF

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: As a Principal Electrical Engineer at Helion, you will be at the forefront of designing, implementing, and operating advanced RF circuits and diagnostic systems for Helion’s fusion generators. You will integrate plasma science with high-power electrical engineering to deliver reliable, scalable, and high-fidelity plasma and energy system measurements that directly inform performance optimization, generator commissioning, and future device development. You will work across physics, controls, machine operations, and engineering disciplines to ensure instrumentation, diagnostics, and electrical subsystems meet stringent experimental and operational requirements. This is an onsite role that reports directly to our Director of Plasma and Nuclear Science at our Everett, WA office. You Will: - Lead the end-to-end design, deployment, calibration, and operation of RF and plasma systems, ensuring robust instrumentation that meets experimental and operational performance needs. - Design, test, and troubleshoot high-voltage electrical systems including power delivery to pulsed magnets, energy recovery circuits, and internal power networks used during pulsed generator operation. - Develop and integrate electrical measurement hardware (e.g., probes, magnetic coils, high-speed digitizers, sensor networks) into diagnostic platforms that capture key plasma and power system behaviors. - Collaborate with plasma physicists, electrical engineers, controls engineers, and data scientists to align diagnostic capabilities with live experimental needs and long-term scientific and engineering milestones. - Own the assembly, installation, and commissioning of diagnostic and electrical subsystems across multiple test campaigns, ensuring high data fidelity and compliance with safety and operational standards. - Analyze real-time and post-shot electrical and diagnostic data to extract actionable insights, driving performance improvement and design iteration for both hardware and diagnostics. - Guide the development of high-throughput experimental workflows, instrumentation architecture, and internal methodologies that scale with generator performance and facility growth. - Provide technical leadership in strategic planning and cross-functional roadmap discussions that shape the future of Helion’s fusion experimentation and electrical systems architecture. - Mentor junior scientists and engineers, driving excellent engineering practices, documentation standards, and experimental rigor. Required Skills: - Advanced degree (Ph.D. preferred) in Electrical Engineering, Physics, Plasma Science, or a closely related discipline with significant hands-on experimental experience. - 10+ years of advanced laboratory and experimental engineering experience, including design and deployment of RF systems and high-voltage measurement hardware in plasma, fusion, or comparable environments. - Deep experience in high-voltage electrical systems, includ