Principal Capacitor Engineer

About HelionWe 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 $1.5 billion from long-time investors such as Sam Altman, Mithril, and Capricorn Investment Group as well as new investors including Thrive Capital, LightSpeed Venture Capital, SoftBank, and others to propel us forward. Our current prototype, Polaris, has reached record-breaking plasma temperatures of 150 million degrees Celsius (13 keV). Helion is continuing to iterate and on the path to the world's first fusion power plant, Orion.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 DoingAs a Principal Capacitor Design Engineer at Helion, you will lead the design, development, and scaling of custom high-voltage, pulsed-power capacitors that are core to Helion’s fusion generators. You will own capacitor architecture from first principles through high-volume manufacturing, driving breakthroughs in energy density, reliability, and cost. You will provide deep technical leadership to engineering, manufacturing, and production teams as Helion transitions from prototype builds to the world’s first fusion power plant. You will provide technical leadership, organize work, set priorities, and advance Helion’s mission to deliver clean power in a reliable and cost-effective manner. This role is onsite at our headquarters in Everett, WA.You WillLead the full lifecycle of capacitor development—requirements definition, physics-based modeling, internal design, materials selection, prototyping, testing, and scaling into high-throughput manufacturingDrive the development of low-inductance, high-reliability pulsed capacitors capable of <1 ms, multi-megampere operation, while optimizing for energy density, manufacturability, cost, and lifetime performanceDefine critical material specifications, qualification criteria, manufacturing processes, and high-voltage pulsed-power test methods for Helion’s custom capacitor systemsProvide technical leadership and mentorship to engineers, technicians, and assemblers, guiding architecture decisions, test interpretation, and iterative design improvementsLead failure analysis, lifetime modeling, thermal analysis, and root-cause investigations to strengthen capacitor reliability and production consistencyPartner closely with pulsed-power electrical engineers to align capacitor design with system-level circuit performance targetsDirect the testing, characterization, and evaluation of internally built and supplier-provided capacitors; analyze data and drive continuous improvement with internal teams and external vendorsOwn long-term capacitor technology strategy, identifying opportunities to reduce risk, introduce advanced materials, and integrate emerging capacitor technologiesRequired SkillsBachelor’s or Master’s degree in Engineering or Physics15+ years of deep experience in pulsed-power capacitor design and manufacturing, including internal construction, low-inductance layout, simulation, materials processing, fabrication, high-voltage testing, and lifetime predictionDemonstrated expertise in dielectric physics: electrical/thermal aging, breakdown behavior, complex permittivity, frequency and temperature dependence, and high-field effectsProven ability to lead capacitor design from concept through high-volume production, including scaling throughput and establishing robust manufacturing processesHands-on experience with rapid prototyping, iterative testing, and high-energy pulsed-power qualificationStrong capability in failure analysis, thermal modeling, and performance evaluation under extreme electrical and thermal stressTrack record of effective cross-functional collaboration with electrical engineering, manufacturing, supply chain, and production teamsAbility to drive technical decision-making, mentor engineers, and set long-term architecture and process standardsStrong communication skills and ability to translate complex physical and engineering concepts into actionable design directions#LI-Onsite #LI-KL1BenefitsOur 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 stipendHelion is an equal opportunity employer and value diversity at our company. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. If you need assistance or an accommodation during the interview process, please let us know.Compensation Range: $214K - $255KLocationEverett, WAEmployment TypeFull timeLocation TypeOn-siteDepartment Mechanical EngineeringCompensation$214K – $255K