Energetic particle physics in fusion research in preparation for burning plasma experiments

Gorelenkov, N. N.; Pinches, S. D.; Toi, K.

doi:10.1088/0029-5515/54/12/125001

Cited by 222 publications

(218 citation statements)

References 568 publications

(1,106 reference statements)

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“…As shown in Fig. 9, 32 STs can explore a very wide energetic particle parameter space. The most commonly excited toroidal Alfv en eigenmodes (TAEs) showed modification and stabilization in high b ST regimes.…”

Section: A Overviewmentioning

confidence: 99%

Recent progress on spherical torus research

Ono

Kaita

2015

Physics of Plasmas

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The spherical torus or spherical tokamak (ST) is a member of the tokamak family with its aspect ratio (A = R0/a) reduced to A ∼ 1.5, well below the normal tokamak operating range of A ≥ 2.5. As the aspect ratio is reduced, the ideal tokamak beta β (radio of plasma to magnetic pressure) stability limit increases rapidly, approximately as β ∼ 1/A. The plasma current it can sustain for a given edge safety factor q-95 also increases rapidly. Because of the above, as well as the natural elongation κ, which makes its plasma shape appear spherical, the ST configuration can yield exceptionally high tokamak performance in a compact geometry. Due to its compactness and high performance, the ST configuration has various near term applications, including a compact fusion neutron source with low tritium consumption, in addition to its longer term goal of an attractive fusion energy power source. Since the start of the two mega-ampere class ST facilities in 2000, the National Spherical Torus Experiment in the United States and Mega Ampere Spherical Tokamak in UK, active ST research has been conducted worldwide. More than 16 ST research facilities operating during this period have achieved remarkable advances in all fusion science areas, involving fundamental fusion energy science as well as innovation. These results suggest exciting future prospects for ST research both near term and longer term. The present paper reviews the scientific progress made by the worldwide ST research community during this new mega-ampere-ST era.

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Section: A Overviewmentioning

confidence: 99%

Recent progress on spherical torus research

Ono

Kaita

2015

Physics of Plasmas

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“…However, these ions can also interact strongly with a range of corelocalized MHD modes, causing increased fast-ion losses and heating of the first wall [1]. Understanding the behaviour and transport of fast ions in the presence of these modes is hence important for assessing the fusion performance and stable operating regimes of future devices.…”

Section: Introductionmentioning

confidence: 99%

Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

et al. 2016

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Abstract. Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices. Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade. These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phasespace measurement volume of about 50% across sawtooth crashes, in good agreement with values predicted with the Kadomtsev sawtooth model implemented in TRANSP and with the sawtooth model in the EBdyna go code. In contrast to the case of sawteeth, we observe no fast-ion redistribution in the presence of fishbone modes. We highlight how CTS measurements can discriminate between different sawtooth models, in particular when aided by multi-diagnostic velocity-space tomography, and briefly discuss our results in light of existing measurements from other fast-ion diagnostics.

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“…The low-n ITG/TEM growth rate is assumed to be a good representative of the zonal flow ExB shearing rate. [6] should be consulted for a general review of energetic particle physics in fusion research preparing for burning plasma experiments. Nearly all previous gyrokinetic studies of EP driven unstable AE modes have assumed a Maxwellian velocity distribution for the EP's.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII-D tilted neutral beam experiments

et al. 2015

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Recent experiments with the DIII-D tilted neutral beam injection (NBI) varying the beam energetic particle (EP) source profiles have provided strong evidence that unstable Alfven eigenmodes (AE) drive stiff EP transport at a critical EP density gradient [Heidbrink et al 2013 Nucl. Fusion 53 093006]. Here the critical gradient is identified by the local AE growth rate being equal to the local ITG/TEM growth rate at the same low toroidal mode number. The growth rates are taken from the gyrokinetic code GYRO. Simulation show that the slowing down beam-like EP distribution has a slightly lower critical gradient than the Maxwellian. The ALPHA EP density transport code [Waltz and Bass 2014 Nucl. Fusion 54 104006], used to validate the model, combines the low-n stiff EP critical density gradient AE mid-core transport with the Angioni et al (2009 Nucl. Fusion 49 055013) energy independent high-n ITG/TEM density transport model controling the central core EP density profile. For the on-axis NBI heated DIII-D shot 146102, while the net loss to the edge is small, about half the birth fast ions are transported from the central core r/a < 0.5 and the central density is about half the slowing down density. These results are in good agreement with experimental fast ion pressure profiles inferred from MSE constrained EFIT equilibria.

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Energetic particle physics in fusion research in preparation for burning plasma experiments

Cited by 222 publications

References 568 publications

Recent progress on spherical torus research

Recent progress on spherical torus research

Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII-D tilted neutral beam experiments

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