Excitation of Alfven eigenmodes by low energy beam ions in the DIII-D and JET tokamaks

Journal Article · Thu May 15 04:00:00 EDT 2008 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2839286· OSTI ID:21120362

Nazikian, R; Gorelenkov, N N; Budny, R V; Fu, G Y; Kramer, G J; Solomon, W M; White, R B ^[1]; Alper, B; Pinches, S D; Sharapov, S E ^[2]; Berk, H L ^[3]; Borba, D ^[4]; Heidbrink, W W ^[5]; Makowski, M A ^[6]; Strait, E J; Van Zeeland, M A ^[7]

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1. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
2. Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)
3. University of Texas at Austin, Austin, Texas 78712 (United States)
4. Euratom/IST Fusion Association, Centro de Fusao Nuclear, Lisboa (Portugal)
5. University of California Irvine, Irvine, California 92697 (United States)
6. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
7. General Atomics, San Diego, California 92186-5608 (United States)

Core localized Alfven eigenmodes in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and Joint European Torus (JET) [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] plasmas are driven by deuterium neutral beam ions traveling well below the Alfven speed. Modes are observed in reverse magnetic shear discharges with deuterium ion velocities as low as 0.23 and 0.16 of the Alfven speed parallel to the magnetic field in DIII-D and JET plasmas, respectively. Ellipticity-induced Alfven eigenmodes in DIII-D and toroidicity-induced Alfven eigenmodes in JET are excited by deuterium ions traveling well below the fundamental passing ion resonance condition, indicating the role of high-order resonances in driving these modes. NOVA-K analysis reveals many high-order resonances as contributing to the mode drive at high central safety factor due to the correspondingly large poloidal orbit width and the decrease in the perpendicular scale length of the modes.

• OSTI ID: 21120362
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 15; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALFVEN WAVES
BEAMS
DEUTERIUM
DEUTERIUM IONS
DOUBLET-3 DEVICE
ELECTRIC DISCHARGES
EXCITATION
JET TOKAMAK
LENGTH
MAGNETIC FIELDS
PLASMA
PLASMA CONFINEMENT
RESONANCE
VELOCITY
WIDTH