Measurements of fast ions and their interactions with MHD activity using neutron emission spectroscopy

C. Hellesen, M. Gatu Johnson, E. Andersson Sundén, S. Conroy, G. Ericsson, J. Eriksson, G. Gorini, T. Johnson, V.G. Kiptily, S.D. Pinches, S.E. Sharapov, H. Sjöstrand, M. Nocente, M. Tardocchi, M. Weiszflog

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Abstract

Ion cyclotron radio frequency (ICRF) heating can produce fast ion populations with energies reaching up to several megaelectronvolts. Here, we present unique measurements of fast ion distributions from an experiment with 3rd harmonic ICRF heating on deuterium beams using neutron emission spectroscopy (NES). From the experiment, very high DD neutron rates were observed, using only modest external heating powers. This was attributed to acceleration of deuterium beam ions to energies up to about 2-3 MeV, where the DD reactivity is on a par with that of the DT reaction. The high neutron rates allowed for observations of changes in the fast deuterium energy distribution on a time scale of 50 ms. Clear correlations were seen between fast deuterium ions in different energy ranges and magnetohydrodynamic activities, such as monster sawteeth and toroidal Alfven eigen modes (TAE). Specifically, NES data showed that the number of deuterons in the region between 1 and 1.5 MeV were decaying significantly during strong TAE activity, while ions with lower energies around 500 keV were not affected. This was attributed to resonances with the TAE modes. © 2010 IAEA, Vienna Printed in the UK & the USA.
Original languageEnglish
Article number084006
Pages (from-to)-
JournalNuclear Fusion
Volume50
Issue number8
DOIs
Publication statusPublished - Aug 2010
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Hellesen, C., Gatu Johnson, M., Andersson Sundén, E., Conroy, S., Ericsson, G., Eriksson, J., ... Weiszflog, M. (2010). Measurements of fast ions and their interactions with MHD activity using neutron emission spectroscopy. Nuclear Fusion, 50(8), -. [084006]. https://doi.org/10.1088/0029-5515/50/8/084006