Tangential Neutral-Beam-Driven Instabilities in the Princeton Beta Experiment

Heidbrink, W. W.; Bol, K.; Buchenauer, D.; Fonck, R.J.; Gammel, G.; Ida, K.; Kaita, R.; Kaye, S. M.; Kugel, H.; LeBlanc, B.P.; Morris, W.; Okabayashi, M.; Powell, E. T.; Šesnić, S.; Takahashi, H.

doi:10.1103/physrevlett.57.835

Cited by 93 publications

(90 citation statements)

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“…66. During tangential injection, the internal frequency of a sawbone is often not much greater than the plasma rotation speed and the reduction in frequency at a burst is only about 10% [354]. Table IV. Detailed, quantitative, agreement of the theoretically predicted frequency with observations has not …”

Section: Idealmentioning

confidence: 99%

The behaviour of fast ions in tokamak experiments

1994

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ABSTRACT. Fast ions with energies significantly larger than the bulk ion temperature are used to heat most tokamak plasmas. Fast ion populations created by fusion reactions, by neutral beam injection and by radiofrequency (RF) heating are usually concentrated in the centre of the plasma. The velocity distribution of these fast ion populations is determined primarily by Coulomb scattering; during wave heating, perpendicular acceleration by the RF waves is also important. Transport of fast ions is typically much slower than thermal transport, except during MHD events. Intense fast ion populations drive collective instabilities. Implications for the behaviour of alpha particles in future devices are discussed.

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Section: Idealmentioning

confidence: 99%

The behaviour of fast ions in tokamak experiments

1994

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“…• In PDX, kink instabilities during parallel injection were just as virulent as the fishbones during perpendicular injection even though the perpendicular j8 was much smaller [22,23].…”

Section: Introductionmentioning

confidence: 98%

The fishbone instability in the DIII-D tokamak

Heidbrink

Sager

1990

Nucl. Fusion

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ABSTRACT. Although most DIII-D plasmas are stable to the fishbone instability, fishbones are sometimes observed when /3 p £ 1.5 and ^ 5 5 x 10 13 cm" 3 . These bursts are usually of minor significance operationally; however, under one condition, over 50% of the beam power was lost. The angle of beam injection has little effect on the virulence of the instability, suggesting that the fishbone instability in DIII-D is the ion diamagnetic branch of the internal kink.

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“…High-β NBI-driven poloidal magnetic field oscillations in tokamak plasmas in the frequency range ∼ 10 -20 kHz are destabilised with perpendicular and tangential neutral beams and associated with redistribution of the beam ions [24,25]. Trapped and circulating beam-ions resonate with the core-localised m = 1 / n = 1 mode [26].…”

Section: Fishbone Effects On Fast Ion Lossesmentioning

confidence: 99%

Study of Interaction between Fast Ions and MHD Instabilities by Fusion Product Measurements in Joint European Torus

Kiptily

Sharapov

Gaßner

et al. 2013

Plasma and Fusion Research

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Fast ion redistribution and losses caused by plasma disruptions, Toroidal Alfvén Eigenmodes (TAE) and fishbones are measured with a suite of improved gamma-ray diagnostics, Neutral Particle Analyser (NPA), neutron spectrometry, Faraday Cups and a Scintillator Probe (SP). Fast ion populations in the MeV energy range were generated in fusion reactions and were also produced by 3rd harmonic Ion Cyclotron Resonance Heating (ICRH). Significant fast ion losses preceding plasma disruptions were often detected by SP in discharges with high β N . These losses were caused by the m = 2 / n = 1 kink mode and typically occurred at the time of thermal quench, before the current quench. Core-localised TAE modes inside the q = 1 radius causing redistribution of the fast ions in the resonance energy range were directly measured for the first time with the gamma-ray camera, confirming that the TAE instability expels fast ions from inside the q = 1 radius and triggers the monster sawtooth crashes. Energy and pitch angle resolved SP measurements of lost fusion products in the MeV energy range were found to correlate with low-frequency fishbone oscillations driven by 100 keV beam ions. The origin and amplitude of these non-resonant losses are investigated.

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Tangential Neutral-Beam-Driven Instabilities in the Princeton Beta Experiment

Cited by 93 publications

References 9 publications

The behaviour of fast ions in tokamak experiments

The behaviour of fast ions in tokamak experiments

The fishbone instability in the DIII-D tokamak

Study of Interaction between Fast Ions and MHD Instabilities by Fusion Product Measurements in Joint European Torus

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