Ion heating by nonlinear Landau damping of high-n toroidal Alfvén eigenmodes in ITER

Seo, Jaemin; Na, Y.-S.; Hahm, T.S.

doi:10.1088/1741-4326/ac17c0

Cited by 7 publications

(4 citation statements)

References 49 publications

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“…Moreover, nonlinear and non-local interactions of multiple modes (e.g. core and edge-localized or multi-n) can add to damping [23,24]. Nevertheless, these raw damping rate data are important for future devices because, all else constant, AEs may be better stabilized in pre-fusion-power operations with H/He plasmas and therefore more readily destabilized in D/T campaigns.…”

Section: Trends With Average Ion Massmentioning

confidence: 99%

Isotope effects and Alfvén eigenmode stability in JET H, D, T, DT, and He plasmas

Tinguely,

Puglia,

Dowson

et al. 2024

Nucl. Fusion

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While much about Alfvén eigenmode (AE) stability has been explored in previous and current tokamaks, open questions remain for future burning plasma experiments, especially regarding exact stability threshold conditions and related isotope effects; the latter, of course, requiring good knowledge of the plasma ion composition. In the JET tokamak, eight in-vessel antennas actively excite stable AEs, from which their frequencies, toroidal mode numbers, and net damping rates are assessed. The effective ion mass can also be inferred using measurements of the plasma density and magnetic geometry. Thousands of AE stability measurements have been collected by the Alfvén Eigenmode Active Diagnostic in hundreds of JET plasmas during the recent Hydrogen, Deuterium, Tritium, DT, and Helium-4 campaigns. In this novel AE stability database, spanning all four main ion species, damping is observed to decrease with increasing Hydrogenic mass, but increase for Helium, a trend consistent with radiative damping as the dominant damping mechanism. These data are important for confident predictions of AE stability in both non-nuclear (H/He) and nuclear (D/T) operations in future devices. In particular, if radiative damping plays a significant role in overall stability, some AEs could be more easily destabilized in D/T plasmas than their H/He reference pulses, even before considering fast ion and alpha particle drive. Active MHD spectroscopy is also employed on select HD, HT, and DT plasmas to infer the effective ion mass, thereby closing the loop on isotope analysis and demonstrating a complementary method to typical diagnosis of the isotope ratio.

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Section: Trends With Average Ion Massmentioning

confidence: 99%

Isotope effects and Alfvén eigenmode stability in JET H, D, T, DT, and He plasmas

Tinguely,

Puglia,

Dowson

et al. 2024

Nucl. Fusion

View full text Add to dashboard Cite

show abstract

“…As a result, in future reactors such as ITER and CFETR [3,4] with a/ρ h O (10), the most unstable modes are characterized by n O (10) with many modes having comparable linear growth rates [21]. Thus, nonlinear mode coupling is expected to be a channel for effectively saturating SAW instabilities and modifying the perturbation spectrum [14,[33][34][35][36][37], among which, alpha-channeling through TAE decaying into modes prone to ion Landau damping are proposed and analyzed in references [14,36,38,39], which is shown to effectively transfer fusion alpha particle power to fuel ions, in addition to nonlinearly saturate TAEs.…”

Section: Introductionmentioning

confidence: 99%

Core localized alpha-channeling via low frequency Alfvén mode generation in reversed shear scenarios

Wei¹,

Wang²,

Chen³

et al. 2022

Nucl. Fusion

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A novel channel for fuel ions heating in tokamak core plasma is proposed and analyzed using nonlinear gyrokinetic theory. The channel is achieved via spontaneous decay of reversed shear Alfvén eigenmode (RSAE) into low frequency Alfvén modes (LFAM), which then heat fuel ions via collisionless ion Landau damping. The conditions for RSAE spontaneous decay are investigated, and the saturation level and the consequent fuel ion heating rate are also derived. The channel is expected to be crucial for future reactors operating under reversed shear configurations, where fusion alpha particles are generated in the tokamak core with the magnetic shear being, typically, reversed, and there is a dense RSAE spectrum due to the small alpha particle characteristic dimensionless orbits.

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“…Thus, nonlinear mode coupling is expected to be a channel for effectively saturating SAW instabilities and modifying the perturbation spectrum [14,[33][34][35][36][37], among which, alphachanneling through TAE decaying into modes prone to ion Landau damping are proposed and analyzed in Refs. [14,36,38,39], which is shown to effectively transfer fusion alpha particle power to fuel ions, in addition to nonlinearly saturate TAEs.…”

Section: Introductionmentioning

confidence: 99%

Core localized alpha-channeling via low frequency Alfven mode generation in reversed shear scenarios

Wei¹,

Wang²,

Chen³

et al. 2022

Preprint

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A novel channel for fuel ions heating in tokamak core plasma is proposed and analyzed using nonlinear gyrokinetic theory. The channel is achieved via spontaneous decay of reversed shear Alfvén eigenmode (RSAE) into low frequency Alfvén modes (LFAM), which then heat fuel ions via collisionless ion Landau damping. The conditions for RSAE spontaneous decay are investigated, and the saturation level and the consequent fuel ion heating rate are also derived. The channel is expected to be crucial for future reactors operating under reversed shear configurations, where fusion alpha particles are generated in the tokamak core where the magnetic shear is typically reversed, and there is a dense RSAE spectrum due to the small alpha particle characteristic dimensionless orbits.

show abstract

Ion heating by nonlinear Landau damping of high-n toroidal Alfvén eigenmodes in ITER

Cited by 7 publications

References 49 publications

Isotope effects and Alfvén eigenmode stability in JET H, D, T, DT, and He plasmas

Isotope effects and Alfvén eigenmode stability in JET H, D, T, DT, and He plasmas

Core localized alpha-channeling via low frequency Alfvén mode generation in reversed shear scenarios

Core localized alpha-channeling via low frequency Alfven mode generation in reversed shear scenarios

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