---
title: 'Principal Magnet Cryogenics Engineer at Thea Energy'
canonical: 'https://feeny.ai/job/principal-magnet-cryogenics-engineer-thea-energy-kearny-jnaw8e41qpnb'
type: 'job'
last_seen: '2026-10-14'
---

# Principal Magnet Cryogenics Engineer at Thea Energy

- **Company:** Thea Energy
- **Location:** Kearny, NJ
- **Compensation:** $190k–$215k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-09-24
- **Last confirmed live:** 2026-10-14
- **Apply:** https://jobs.lever.co/thea.energy/4d47734f-5cb9-4488-9f25-12e808956863

## Job description

About Thea Energy: Thea Energy is leveraging recent breakthroughs in stellarator physics and engineering to create a faster and simpler approach to commercializing fusion energy. The company is reinventing the stellarator using computer-controlled arrays of planar coils thereby replacing the intricate, complex modular magnets required in all other stellarator architectures. Thea Energy is on a mission to create a limitless source of zero emission energy for a sustainable future.

Position Overview: We are seeking a Principal Magnet Cryogenics Engineer with over 10-15 years of industry experience to lead the complete program lifecycle—from concept through commissioning—of large-scale cabled High-Temperature Superconducting (HTS) magnet systems for next-generation fusion reactors.

In this role, you will hold end-to-end technical ownership for the cryogenic design, thermal-hydraulic modelling, forced-flow cooling distribution, and cryogenic integration of large-scale CICC (Cable-in-Conduit Conductor) or advanced stacked-tape HTS magnets. You will bridge megawatt scale cryogenic plant engineering with microscopic thermal-hydraulic magnet behaviour, leading multi-disciplinary teams through multi-million-dollar hardware deliverables.

Key Responsibilities:

- Program Lifecycle Ownership: Lead the complete lifecycle (Conceptual, Preliminary, Detailed Design, Qualification, Fabrication, Assembly, Commissioning, and Decommissioning) for large-scale HTS fusion magnet cryogenic systems.
- Cryo-Thermal System Architecture: Design, model, and validategaseous helium (gHe), or sub-cooled liquid nitrogen (sLN2) thermal management systems tailored to high-field HTS cabled conductors (stacked HTS conductors).
- Thermal-Hydraulic Modeling: Perform dynamic thermal-hydraulic analysis, transient load modelling (nuclear heating, AC losses, eddy currents, ramp rates), and margin calculations under operational and fault conditions.
- Quench & Fault Management: Own the cryogenic response strategy during quench events, including rapid helium expansion, overpressure relief sizing, burst disc integration, and thermo-mechanical stress containment.
- Large-Scale Infrastructure & Plant Integration: Define requirements for mega-watt class cryogenic plants, cold compressors, heat exchangers, sub-coolers, helium distribution boxes (valve boxes), and low-heat-leak transfer lines.
- Joints & Current Leads: Oversee cryogenic thermal management for high-current demountable or permanent HTS joints and conduction-cooled hybrid (HTS/LTS) gas-cooled current leads (60+ kA).
- Vendor & Subcontractor Governance: Manage major sub-contracts for large-scale cryogenic infrastructure, conductor fabrication, pressure vessels, and vacuum insulated systems (cryostats).
- V&V and Commissioning: Plan and execute full-scale cryogenic and high-current magnet test campaigns, leading cool-down, steady-state operation, quench mitigation, and warm-up procedures.

Required Experience:

- 10-15+ Years of Direct Experience in cryogenic engineering and thermal-hydraulic design for superconducting magnet systems, with a primary focus on HTS tape/cable architectures (REBCO/BSCCO).
- Large-Scale Fusion/Physics Program Delivery: Proven track record of ownership over large-scale (> $10M+) magnet work packages within fusion energy programs (e.g., W7x, ITER, JT60SA, KSTAR, DEMO) or major scientific facilities (e.g., CERN, FERMILAB).
- Cabled HTS Architecture: Demonstrated expertise in high-current (tens of kA) cabled HTS configurations (e.g., Cable-in-Conduit Conductors, stacked tape conductors) and forced-flow cooling strategies.
- Full Lifecycle Track Record: Experience taking at least one major superconducting magnet or cryogenic system from initial concept through initial cool-down and operational validation.
- Regulatory & Code Compliance: Deep familiarity with pressure vessel standards applied to cryogenic temperatures (ASME BPVC Section VIII, EN 13445, B31.3) and cryogenic safety standards (ISO 21010/CGA).

Technical Knowledge

- HTS Material Physics: Solid understanding of critical surfaces for REBCO coated conductors, strain sensitivity, thermal margin assessment, and current sharing regimes.
- Cryogenic Fluids & Thermophysical Properties: Mastery of low-temperature fluid dynamics (gHe, sLN2) using database tools.
- Transient Thermal Analysis: Deep domain knowledge of AC losses (coupling, hysteresis, flux creep) nuclear volumetric heating, heat-leak budgets, and conduction/radiation thermal shielding (MLI design).
- Instrumentation & Controls: Extensive knowledge of low-temperature thermometry (Cernox, TVO, optical fibers/FBG), cryogenic flow meters, pressure transducers, and cryogenic valve telemetry.

## Skills & Competencies

- Computational Tools: Proficiency in finite element analysis (FEA) and thermal-hydraulic system modeling tools (e.g., COMSOL Multiphysics, ANSYS Thermal/CFD, MATLAB/Simulink).
- System Engineering & Requirements Flowdown: Capability to write clear system requirement documents (SRDs), interface control documents (ICDs), and lead major design reviews (CoDR, PDR, CDR).
- Leadership & Team Mentorship: Demonstrated ability to lead cross-functional engineering teams (structural, electrical, vacuum, systems) and mentor junior magnet/cryogenic engineers.
- Strategic Risk Mitigation: Mastery of FMEA, applied to cryogenic system failures, vacuum loss (loss of vacuum/L VAC), and runaway quench scenarios.

## #LI-RD1

Company Benefits:

- Comprehensive health benefits (e.g. medical/dental/vision)
- Employee equity stock options
- 20 days PTO

It’s not necessary to meet all of the skillsets outlined above. Please feel free to send us a note and tell us why you would still be a great fit for this role or Thea Energy.

Diversity and Inclusion: Thea Energy is an equal opportunity employer committed to creating a company of diverse backgrounds. By creating a diverse environment, we will bring new ideas and approaches to solving some of the world’s hardest (and most important) problems. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender, sexual orientation, gender identity or expression, national origin, family or marital status, age, disability, veteran’s status, or other characteristic protected by applicable laws and regulations.

## About Thea Energy

## Company Overview
- **One-liner**: Thea Energy is developing a simplified, economical stellarator fusion energy system using arrays of mass-manufacturable planar magnets and dynamic software controls.
- **Entity Type**: Private (Startup; founded in 2022)
- **Headquarters**: Kearny, New Jersey, USA
- **Founded**: 2022
- **Founders**: Founded with technology developed at Princeton University (specific founder names not publicly listed on main site).

## Core Business
- **Primary industry**: Fusion Energy / Clean Energy / Climate Tech
- **Target customers**: Utilities, grid operators, industrial energy users, and governments seeking baseload, zero-emission power generation.
- **Mission**: "To create a limitless source of zero emission energy for the future of humanity." [thea.energy](https://thea.energy/)

## Products & Services
- **Eos (Neutron Source Stellarator)**: A near-term commercial neutron source designed to achieve world-leading fusion performance and de-risk their first fusion power plant. [thea.energy](https://thea.energy/)
- **Helios (Fusion Power Plant)**: The company’s first planned full-scale fusion power plant, intended for commercial electricity generation. [thea.energy](https://thea.energy/)
- **Software-Defined Magnetics Platform**: The core technology differentiator—replacing complex, expensive 3D magnet coils with arrays of simpler, mass-manufacturable planar magnets controlled by a sophisticated software stack. This transfers hardware complexity into the digital realm. [thea.energy](https://thea.energy/)

## Market Standing
- **Valuation / Total Funding**: Not publicly disclosed.
- **Key Metric**: Private startup; notable for its technological breakthrough rather than public revenue. The company has active job postings (41 roles listed on Indeed) and is in a high-growth hiring phase. [indeed.com](https://www.indeed.com/cmp/Thea-Energy/about)
- **Notable Investors/Partners**: Announced a collaboration with **NVIDIA**, **Synopsys Inc**, **Argonne National Laboratory**, and **Princeton Plasma Physics Laboratory (PPPL)** to build the first digital twin of a stellarator fusion power plant using AI physics and engineering. [indeed.com](https://www.indeed.com/cmp/Thea-Energy/about)
- **Growth Signals**: Rapidly growing team; active hiring across engineering, supply chain, finance, and marketing roles; partnership with major tech and national lab players; progression from a science project (Eos) toward a commercial power plant (Helios).

## Competitive Advantages
- **Planar Magnet Arrays**: Replaces the prohibitively complex and expensive 3D coils of traditional stellarators with simple, mass-manufacturable planar magnets. This radically reduces cost and manufacturing complexity. [thea.energy](https://thea.energy/)
- **Software-First Approach**: Transfers the geometric complexity from hardware to a dynamic software control system, leveraging decades of progress in computing and controls to simplify the physical build. [thea.energy](https://thea.energy/)
- **Stellarator Advantage**: The stellarator is the only magnetic confinement system that creates all required fields with superconducting coils, enabling steady-state operation (no plasma disruptions), which is a key advantage over tokamaks. [thea.energy](https://thea.energy/)

## Strategic Focus
- **Commercialization of Eos**: Achieving near-term fusion performance and commercial operation with their neutron source stellarator.
- **De-risking Helios**: Using Eos as a stepping stone to validate technology and reduce risk for their first full-scale fusion power plant.
- **Digital Twin Development**: Leveraging AI and simulation (with NVIDIA, Synopsys, Argonne, PPPL) to accelerate design, operation, and optimization of their fusion systems.
- **Scaling the Organization**: Building out a multi-disciplinary team spanning fusion science, engineering, supply chain, and business functions.

## Why Work Here
- **Mission-Driven Work**: Opportunity to work on one of the biggest challenges facing humanity—creating limitless, zero-emission energy. [thea.energy](https://thea.energy/careers/)
- **Culture**: Described as dynamic, flexible, and adaptive, balancing strong individual autonomy with a collective team spirit. Employees are empowered to take ownership of their career growth. [thea.energy](https://thea.energy/careers/)
- **Diversity & Inclusion**: Explicitly committed to building a diverse workplace and encourages applications even if candidates don't meet every listed requirement. [thea.energy](https://thea.energy/careers/)
- **Work Model**: Roles are listed as **On-site** in Kearny, NJ (for most technical and corporate roles) and some internships. [jobs.lever.co/thea.energy](https://jobs.lever.co/thea.energy)
- **Benefits**: Competitive salaries, health benefits (medical/dental/vision), employee equity, 20 days PTO, paid holidays and sick time, paid parental leave, 401k, life and disability insurance, and office perks. [thea.energy](https://thea.energy/careers/)

## Sources
1. [thea.energy](https://thea.energy/)
2. [thea.energy/about-us](https://thea.energy/about-us/)
3. [thea.energy/careers](https://thea.energy/careers/)
4. [jobs.lever.co/thea.energy](https://jobs.lever.co/thea.energy)
5. [indeed.com](https://www.indeed.com/cmp/Thea-Energy/about)

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