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

Abstract

According to the article, 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.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. TAE Technologies, Inc., Foothill Ranch, CA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); UT-Battelle LLC/ORNL, Oak Ridge, TN (Unted States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1565755
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Nature Physics
Additional Journal Information:
Journal Volume: 15; Journal Issue: 3; Journal ID: ISSN 1745-2473
Publisher:
Nature Publishing Group (NPG)
Country of Publication:
United States
Language:
English
Subject:
Physics

Citation Formats

Magee, R. M., Necas, A., Clary, R., Korepanov, S., Nicks, S., Roche, T., Thompson, M. C., Binderbauer, M. W., and Tajima, T. Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment. United States: N. p., 2019. Web. doi:10.1038/s41567-018-0389-0.
Magee, R. M., Necas, A., Clary, R., Korepanov, S., Nicks, S., Roche, T., Thompson, M. C., Binderbauer, M. W., & Tajima, T. Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment. United States. doi:10.1038/s41567-018-0389-0.
Magee, R. M., Necas, A., Clary, R., Korepanov, S., Nicks, S., Roche, T., Thompson, M. C., Binderbauer, M. W., and Tajima, T. Mon . "Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment". United States. doi:10.1038/s41567-018-0389-0.
@article{osti_1565755,
title = {Direct observation of ion acceleration from a beam-driven wave in a magnetic fusion experiment},
author = {Magee, R. M. and Necas, A. and Clary, R. and Korepanov, S. and Nicks, S. and Roche, T. and Thompson, M. C. and Binderbauer, M. W. and Tajima, T.},
abstractNote = {According to the article, 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.},
doi = {10.1038/s41567-018-0389-0},
journal = {Nature Physics},
issn = {1745-2473},
number = 3,
volume = 15,
place = {United States},
year = {2019},
month = {1}
}

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