A mechanism for beam-driven excitation of ion cyclotron harmonic waves in the Tokamak Fusion Test Reactor

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

DOI:https://doi.org/10.1063/1.870489· OSTI ID:7000558

Dendy, R O; McClements, K G; Lashmore-Davies, C N ^[1]; Majeski, R; Cauffman, S ^[2]

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1. UKAEA Government Division, Fusion, Euratom/UKAEA Fusion Association, Culham, Abingdon, Oxfordshire, OX14 3DB (United Kingdom)
2. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

A mechanism is proposed for the excitation of waves at harmonics of the injected ion cyclotron frequencies in neutral beam-heated discharges in the Tokamak Fusion Test Reactor (TFTR) [[ital Proceedings] [ital of] [ital the] 17[ital th] [ital European] [ital Conference] [ital on] [ital Controlled] [ital Fusion] [ital and] [ital Plasma] [ital Heating] (European Physical Society, Petit-Lancy, Switzerland, 1990), p. 1540]. Such waves are observed to originate from the outer midplane edge of the plasma. It is shown that ion cyclotron harmonic waves can be destabilized by a low concentration of sub-Alfvenic deuterium or tritium beam ions, provided these ions have a narrow distribution of speeds parallel to the magnetic field. Such a distribution is likely to occur in the edge plasma, close to the point of beam injection. The predicted instability gives rise to wave emission at propagation angles lying almost perpendicular to the field. In contrast to the magnetoacoustic cyclotron instability proposed as an excitation mechanism for fusion-product-driven ion cyclotron emission in the Joint European Torus (JET) [Phys. Plasmas [bold 1], 1918 (1994)], the instability proposed here does not involve resonant fast Alfven and ion Bernstein waves, and can be driven by sub-Alfvenic energetic ions. It is concluded that the observed emission from TFTR can be driven by beam ions.

• OSTI ID: 7000558
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:10; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700350* -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
BEAM INJECTION HEATING
CHARGED PARTICLES
CLOSED PLASMA DEVICES
CYCLOTRON HARMONICS
CYCLOTRON RESONANCE
DEUTERIUM IONS
HARMONICS
HEATING
INSTABILITY
ION CYCLOTRON-RESONANCE
IONS
OSCILLATIONS
PLASMA HEATING
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RESONANCE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRITIUM IONS