High Efficiency, Megawatt-Class Gyrotrons for Instability Control of Burning-Plasma Machines

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Framingham, Massachusetts
Project Term:
03/22/2021 - 03/21/2024

Critical Need:

For more than 60 years, fusion research and development (R&D) has focused on attaining the required fuel density, temperature, and energy confinement time of the plasma fuel of a viable fusion energy system. Currently, relatively modest investments have been made in the required and equally critical enabling technologies and advanced materials surrounding the plasma fuel. The GAMOW program supports innovative R&D that will help establish both the technical and commercial viability of (i) all the required technologies and subsystems between the fusion plasma and the balance of plant, (ii) cost-effective, high-efficiency, high-duty-cycle driver technologies, and (iii) novel fusion materials and advanced manufacturing of these materials.

Project Innovation + Advantages:

Prototype burning-plasma magnetic-fusion devices must operate at long pulse lengths to support power generation, making them susceptible to catastrophic disruption from plasma instabilities. Electron cyclotron heating and current drive powered by megawatt-level gyrotrons (vacuum electron devices that generate high-power, high-frequency radiation) are the most effective ways to heat and stabilize such plasmas. Megawatt-class gyrotrons are large, expensive to build and operate, inefficient, and have limited frequency and device lifetime. Bridge 12 Technologies aims to develop and build a 1-MW, 250-GHz gyrotron demonstrator with a total efficiency >65 % that can be used in cost-effective, breakeven-class magnetic-fusion devices at operating parameters relevant for a commercial fusion power plant. The team will build one of the most expensive parts of the gyrotron, the collector, using additive manufacturing with advanced copper alloys allowing for higher performance, robustness, and cost-effectiveness. If successful, the technology will reduce capital and operational costs of a fusion plant and improve the heating system's reliability.

Potential Impact:

Successful development of fusion energy science and technology could lead to a safe, carbon-free, abundant energy source for developed and emerging economies.


The GAMOW program will advance American leadership in fusion energy science and technology.


If successfully developed and commercialized, fusion energy can provide abundant, zero-carbon energy.


Advances in GAMOW’s technical areas will help accelerate progress toward commercial fusion energy and a new zero-carbon energy economy.


ARPA-E Program Director:
Dr. Ahmed Diallo
Project Contact:
Dr. Jagadishwar Sirigiri
Press and General Inquiries Email:
Project Contact Email:


Oak Ridge National Laboratory

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