Published April 2006 | Version v1
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Observation of confinement degradation of energetic ion due to Alfven eigenmodes in weak shear plasmas on JT-60U

  • 1. Japan Atomic Eneryg Agency, Fusion Research and Development Directorate, Naka, Ibaraki (Japan)

Description

Confinement degradation due to Alfven Eigenmodes has been investigated with negative ion based injection at ∼ 370 keV into weak shear plasmas on JT-60U. The AEs with a rapid frequency sweeping and then saturation as the minimum value of safety factor (qmin) decrease have been observed. These frequency behavior can be explained by reversed-shear induced AE (RSAE) and the transition from RSAE to TAE. Reduction rate of total neutron emission rate in the presence of AEs is evaluated by calculation with Orbit Following Monte-Carlo code taking into account changing in bulk plasmas. The changes in total neutron emission rate and CX-NP flux suggested energetic ion transport due to these AEs. The evolution indicates confinement of energetic ions is degraded due to AEs. In particular, it is found confinement degradation is maximum during transition from RSAE to TAE and the maximum reduction rate (ΔSn/Sn)MAX is estimated ∼45%. (author)

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Part of:
Proceedings of the 9th IAEA technical meeting on 'energetic particles in magnetic confinement systems'

Additional details

Publishing Information

Imprint Title
Proceedings of the 9th IAEA technical meeting on 'energetic particles in magnetic confinement systems'
Imprint Pagination
217 p.
Journal Page Range
p. 5-11
Report number
NIFS-PROC--63

Conference

Title
9. IAEA technical meeting on 'energetic particles in magnetic confinement systems'
Dates
9-11 Nov 2005
Place
Takayama, Gifu (Japan)

Optional Information

Notes
21 refs., 8 figs.