The excitation of obliquely propagating fast Alfven waves at fusion ion cyclotron harmonics

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870647· OSTI ID:6693189

Dendy, R O; Lashmore-Davies, C N; McClements, K G ^[1]; Cottrell, G A ^[2]

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1. AEA Technology (Euratom/UKAEA Fusion Association), Fusion, Culham, Abingdon, Oxfordshire, OX14 3DB (United Kingdom)
2. JET Joint Undertaking, Abingdon, Oxfordshire, OX14 3EA (United Kingdom)

The theory of the magnetoacoustic cyclotron instability, which has been proposed as a mechanism for suprathermal ion cyclotron harmonic emission observed in large tokamaks, is generalized to include finite parallel wave number [ital k][sub [parallel]]. This extension introduces significant new physics: the obliquely propagating fast Alfven wave can undergo cyclotron resonant interactions with thermal and fusion ions, which affects the instability driving and damping mechanisms. The velocity--space distribution of the fusion ions is modeled by a drifting ring, which approximates the distribution calculated for the emitting region in tritium experiments on the Joint European Torus (JET) [Cottrell [ital et] [ital al]., Nucl. Fusion [bold 33], 1365 (1993)]. Linear instability can occur simultaneously at the fusion ion cyclotron frequency and all its harmonics when the fusion ion concentration is extremely low, because the finite [ital k][sub [parallel]] gives rise to a Doppler shift, which decouples cyclotron damping due to thermal ions from wave growth associated with fusion ions. Doppler shifts associated with finite [ital k][sub [parallel]] may also be related to the observed splitting of harmonic emission lines.

• OSTI ID: 6693189
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:6; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ACOUSTICS
ALFVEN WAVES
BERNSTEIN MODE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CLOSED PLASMA DEVICES
CYCLOTRON HARMONICS
CYCLOTRON INSTABILITY
CYCLOTRON RESONANCE
DISPERSION RELATIONS
DOPPLER EFFECT
HARMONICS
HYDROGEN ISOTOPES
HYDROMAGNETIC WAVES
INSTABILITY
ION CYCLOTRON-RESONANCE
ISOTOPES
LIGHT NUCLEI
MAGNETOACOUSTICS
NUCLEI
ODD-EVEN NUCLEI
OSCILLATION MODES
OSCILLATIONS
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RADIOISOTOPES
RESONANCE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRITIUM
YEARS LIVING RADIOISOTOPES