Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment

ABSTRACT Efficiently heating a magnetically confined plasma to thermonuclear temperatures remains a central issue in fusion energy research. One well-established technique is to inject beams

of neutral particles into the plasma, a process known as neutral beam injection. In the classical picture, fast ions generated from neutral beam injection predominantly heat electrons as

they are slowed by friction. This electron heat is then collisionally coupled to the plasma ions, which comprise the fusion fuel. Fast ions can also drive plasma waves, which divert energy

from the fuel and can degrade confinement. Here we present new observations from a field reversed configuration plasma in which a beam-driven wave in the open field line region couples

directly to fuel ions, drawing a high-energy tail on subcollisional timescales that dramatically enhances the fusion rate. This mode therefore allows the beam energy to bypass the electron

channel and does so without having a deleterious effect on global plasma confinement. Our results demonstrate a means of directly and non-destructively coupling energy from fast ions to

plasma ions, which may pave the way for improved neutral beam injection heating efficiency or the prevention of ash accumulation with alpha channelling. Access through your institution Buy

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ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS GENERATION OF FIELD-REVERSED

CONFIGURATIONS VIA NEUTRAL BEAM INJECTION Article Open access 12 April 2025 ENHANCED PERFORMANCE IN FUSION PLASMAS THROUGH TURBULENCE SUPPRESSION BY MEGAELECTRONVOLT IONS Article 30 June

2022 HOW FAST IONS MITIGATE TURBULENCE AND ENHANCE CONFINEMENT IN TOKAMAK FUSION PLASMAS Article 26 March 2025 DATA AVAILABILITY The data that support the plots within this paper and other

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  Google Scholar  Download references ACKNOWLEDGEMENTS The authors thank the investors for their support of TAE Technologies and the TAE and Budker teams for their contributions to this

project. Special thanks go to E. Granstedt and E. Trask for help with the design of the experiment. This research used resources of the Oak Ridge Leadership Computing Facility, which is a

DOE Office of Science User Facility supported under contract no. DE-AC05-00OR22725. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * TAE Technologies, Inc., Foothill Ranch, CA, USA R. M. Magee,

 A. Necas, R. Clary, S. Korepanov, S. Nicks, T. Roche, M. C. Thompson, M. W. Binderbauer & T. Tajima Authors * R. M. Magee View author publications You can also search for this author

inPubMed Google Scholar * A. Necas View author publications You can also search for this author inPubMed Google Scholar * R. Clary View author publications You can also search for this

author inPubMed Google Scholar * S. Korepanov View author publications You can also search for this author inPubMed Google Scholar * S. Nicks View author publications You can also search for

this author inPubMed Google Scholar * T. Roche View author publications You can also search for this author inPubMed Google Scholar * M. C. Thompson View author publications You can also

search for this author inPubMed Google Scholar * M. W. Binderbauer View author publications You can also search for this author inPubMed Google Scholar * T. Tajima View author publications

You can also search for this author inPubMed Google Scholar CONTRIBUTIONS R.M.M. contributed neutron measurements and neutron calculations, created all the figures and wrote the majority of

the text. A.N. ran the PIC simulations, provided output data, and provided text for the ‘Simulation and theory’ section. R.C. provided NPA measurements. S.K. provided neutral beam injection.

S.N. provided the analytical theory for benchmarking. T.R. and M.C.T. provided magnetic data. M.W.B. is the driving force behind the C-2U device and helped edited the text. T.T. provided

theoretical interpretation of the experimental and simulation data and contributed significantly to the editing of the text. CORRESPONDING AUTHOR Correspondence to R. M. Magee. ETHICS

DECLARATIONS COMPETING INTERESTS TAE Technologies, Inc. is a private corporation owned and financially supported by its shareholders. Some or all of the authors of this manuscript may have a

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affiliations. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Magee, R.M., Necas, A., Clary, R. _et al._ Direct observation of ion acceleration from a

beam-driven wave in a magnetic fusion experiment. _Nat. Phys._ 15, 281–286 (2019). https://doi.org/10.1038/s41567-018-0389-0 Download citation * Received: 21 February 2017 * Accepted: 30

November 2018 * Published: 14 January 2019 * Issue Date: March 2019 * DOI: https://doi.org/10.1038/s41567-018-0389-0 SHARE THIS ARTICLE Anyone you share the following link with will be able

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