MHD spectroscopy through detecting toroidal Alfvén eigenmodes and Alfvén wave cascades

Sharapov, S. E.; Testa, D.; Alper, B.; Borba, D.; Fasoli, A.; Hawkes, N.; Heeter, R. F.; Mantsinen, M.; Hellermann, M. G. von

doi:10.1016/s0375-9601(01)00588-6

Cited by 165 publications

(191 citation statements)

References 15 publications

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“…Plasmas 24, 082517 (2017) small range. As expected, when q min becomes smaller, the sideband (n ¼ 2 and m ¼ 6 mode) of the n ¼ 2 RSAE 17,18 increases and the mode frequency also increases. The RSAE eventually becomes a Toroidal Alfven Eigenmode (TAE) 19 at q min ¼ 3.25.…”

Section: -4supporting

confidence: 74%

Numerical study on wave-induced beam ion prompt losses in DIII-D tokamak

Feng

Zhu

et al. 2017

Physics of Plasmas

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A numerical study is performed on the coherent beam ion prompt losses driven by Alfv en eigenmodes (AEs) in DIII-D plasmas using realistic parameters and beam ion deposition profiles. The synthetic signal of a fast-ion loss detector (FILD) is calculated for a single AE mode. The first harmonic of the calculated FILD signal is linearly proportional to the AE amplitude with the same AE frequency in agreement with the experimental measurement. The calculated second harmonic is proportional to the square of the first harmonic for typical AE amplitudes. The coefficient of quadratic scaling is found to be sensitive to the AE mode width. The second part of this work considers the AE drive due to coherent prompt loss. It is shown that the loss-induced mode drive is much smaller than the previous estimate and can be ignored for mode stability. Published by AIP Publishing. [http://dx

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Section: -4supporting

confidence: 74%

Numerical study on wave-induced beam ion prompt losses in DIII-D tokamak

Feng

Zhu

et al. 2017

Physics of Plasmas

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“…Assuming, for illustration, non-dispersive waves along with local nonlinear interactions in n-space, the form of Eq. (4.3) becomes that of a discrete Anderson NLSE with randomness, e.g., (Iomin, 2010;Krivolapov et al, 2010;Pikovsky and Shepelyansky, 2008;Shepelyansky, 1993) …”

Section: E Further Remarks On General Theoretical Issues and Broadermentioning

confidence: 99%

Physics of Alfvén waves and energetic particles in burning plasmas

2016

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Dynamics of shear Alfvén waves and energetic particles are crucial to the performance of burning fusion plasmas. This article reviews linear as well as nonlinear physics of shear Alfvén waves and their self-consistent interaction with energetic particles in tokamak fusion devices. More specifically, the review on the linear physics deals with wave spectral properties and collective excitations by energetic particles via wave-particle resonances. The nonlinear physics deals with nonlinear wave-wave interactions as well as nonlinear wave-energetic particle interactions. Both linear as well as nonlinear physics demonstrate the qualitatively important roles played by realistic equilibrium nonuniformities, magnetic field geometries, and the specific radial mode structures in determining the instability evolution, saturation, and, ultimately, energetic-particle transport. These topics are presented within a single unified theoretical framework, where experimental observations and numerical simulation results are referred to elucidate concepts and physics processes.

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“…. RSAEs are usually observed to chirp up to the TAE gap frequency [12]. These plots were generated in the following way: a windowed fast-Fourier transform (FFT) was performed on signals from eight Mirnov coils to produce amplitude and phase in frequency and time space for each coil.…”

Section: Input Datamentioning

confidence: 99%

A sparsity-based method for the analysis of magnetic fluctuations in unevenly-spaced Mirnov coils

Klein

Carfantan

Testa

et al. 2008

Plasma Phys. Control. Fusion

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A new method for identifying toroidal mode numbers in Mirnov data from toroidal plasmas has been found, and benchmarked with simulated and real data from the JET tokamak. Embodied in the SparSpec code, and originally developed for the analysis of unevenly time-sampled astronomical data, this new method fits signals which are unevenly sampled in the toroidal coordinate to a sum of an arbitrarily large number of toroidal modes with integer mode numbers. The method has proven to be extremely robust, and is especially useful for resolving the amplitudes and phases of multiple Alfvén eigenmodes (AEs) which are ringing with the same or nearly the same frequency. The great efficiency with which the SparSpec method detects multiple modes in large datasets suggests that it may be used in real-time applications such as resistive wall mode or tearing mode control, among others. Examples involving unstable AEs as well as stable AEs, (excited by an array of external antennas) in the JET tokamak are used to illustrate the efficacy of the method. Some additional general considerations regarding optimized spatial sampling strategies are also briefly addressed.(Some figures in this article are in colour only in the electronic version) BackgroundAnalysis of magnetic fluctuations external to toroidal plasmas is important for understanding the magneto-hydrodynamic (MHD) properties of the plasma, among other things. These properties affect nearly all aspects of behavior of magnetic confinement, and thus are of interest in topics ranging from gross global plasma stability, control and disruption avoidance to the 5

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MHD spectroscopy through detecting toroidal Alfvén eigenmodes and Alfvén wave cascades

Cited by 165 publications

References 15 publications

Numerical study on wave-induced beam ion prompt losses in DIII-D tokamak

Numerical study on wave-induced beam ion prompt losses in DIII-D tokamak

Physics of Alfvén waves and energetic particles in burning plasmas

A sparsity-based method for the analysis of magnetic fluctuations in unevenly-spaced Mirnov coils

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