Magnetic configuration effects on TAE-induced losses and a comparison with the orbit-following model in the Large Helical Device
- Nagoya University, Japan
- National Institute for Fusion Science, Toki, Japan
- ORNL
Fast-ion losses from Large Helical Device (LHD) plasmas due to toroidal Alfven eigenmodes (TAEs) were measured by a scintillator-based lost fast-ion probe (SLIP) to understand the loss processes. TAE-induced losses measured by the SLIP appeared in energy E ranges of around 50-180 keV with pitch angles. between 35 degrees-45 degrees, and increased with the increase in TAE amplitudes. Position shifts of the magnetic axis due to a finite plasma pressure led not only to an increase in TAE-induced losses but also to a stronger scaling of fast-ion losses on TAE amplitudes. Characteristics of the observed fast-ion losses were compared with a numerical simulation based on orbit-following models in which the TAE fluctuations are taken into account. The calculation indicated that the number of lost fast ions reaching the SLIP increased with the increase in the TAE amplitude at the TAE gap. Moreover, the calculated dependence of fast-ion loss fluxes on the fluctuation amplitude became stronger in the case of large magnetic axis shifts, compared with the case of smaller shifts, as was observed in the experiments. The simulation results agreed qualitatively with the experimental observations in the LHD.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1055196
- Resource Relation:
- Conference: 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems / 5th IAEA Technical Meeting on Theory of Plasma Wave Instabilities, Austin, TX, USA, 20110905, 20110911
- Country of Publication:
- United States
- Language:
- English
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