The alpha channeling effect

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

Original languageEnglish (US)
Title of host publicationRadio Frequency Power in Plasmas
Subtitle of host publicationProceedings of the 21St Topical Conference
EditorsRobert I. Pinsker
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413368
DOIs
StatePublished - Dec 10 2015
Event21st Topical Conference on Radiofrequency Power in Plasmas - Lake Arrowhead, United States
Duration: Apr 27 2015Apr 29 2015

Publication series

NameAIP Conference Proceedings
Volume1689
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other21st Topical Conference on Radiofrequency Power in Plasmas
CountryUnited States
CityLake Arrowhead
Period4/27/154/29/15

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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  • Cite this

    Fisch, N. J. (2015). The alpha channeling effect. In R. I. Pinsker (Ed.), Radio Frequency Power in Plasmas: Proceedings of the 21St Topical Conference [020001] (AIP Conference Proceedings; Vol. 1689). American Institute of Physics Inc.. https://doi.org/10.1063/1.4936463