Nonlinear Dynamics and Complex Behaviors in Magnetized Plasmas of Fusion Interest

Zonca, F.; Chen, L.

doi:10.1063/1.3013781

Cited by 12 publications

(19 citation statements)

References 57 publications

(119 reference statements)

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“…Coupling of the modes can be seen around X * ¼ 0.5. low-frequency fluctuation branches has important implications on a number of kinetic stability problems as well as long time scale plasma behaviors, since realistic tokamak plasmas are characterized by complex behaviors due to the mutual interactions of SAW, MHD, and Drift Wave Turbulence (DWT). 54,55 ACKNOWLEDGMENTS Useful discussions with Liu Chen, Diarmuid Curran, Philipp Lauber, Zhiyong Qiu, and Xin Wang are kindly acknowledged. This work was part of ITER-CN Project No.…”

Section: Conclusion and Discussionmentioning

confidence: 98%

Analytic studies of dispersive properties of shear Alfvén and acoustic wave spectra in tokamaks

Chavdarovski

Zonca

2014

Physics of Plasmas

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The properties of the low frequency shear Alfvén and acoustic wave spectra in toroidal geometry are examined analytically and numerically considering wave particle interactions with magnetically trapped and circulating particles, using the theoretical model described in [I. Chavdarovski and F. Zonca, Plasma Phys. Controlled Fusion 51, 115001 (2009)] and following the framework of the generalized fishbone-like dispersion relation. Effects of trapped particles as well as diamagnetic effects on the frequencies and damping rates of the beta-induced Alfvén eigenmodes, kinetic ballooning modes and beta-induced Alfvén-acoustic eigenmodes are discussed and shown to be crucial to give a proper assessment of mode structure and stability conditions. Present results also demonstrate the mutual coupling of these various branches and suggest that frequency as well as mode polarization are crucial for their identification on the basis of experimental evidence.

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Section: Conclusion and Discussionmentioning

confidence: 98%

Analytic studies of dispersive properties of shear Alfvén and acoustic wave spectra in tokamaks

Chavdarovski

Zonca

2014

Physics of Plasmas

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“…In this respect, one important issue is the determination of hierarchy of relevant non-linear time scales for the various cross-scale couplings including realistic conditions; such as proper equilibrium geometry, spatial nonuniformity, and kinetic effects (Zonca, 2008;Zonca et al, 2013;Zonca and Chen, 2008;Zonca et al, 2015a). Numerical simulations as well as experimental studies are beginning to address these issues.…”

Section: A Energetic Particle Transport In the Presence Of Many Modesmentioning

confidence: 99%

“…IV.D and IV.E). This unified approach also elucidates the role of EPs as mediators of cross scale coupling and long time scale behavior in burning plasmas (Zonca, 2008;Zonca et al, 2013;Zonca and Chen, 2008), reviewed by (Zonca et al, 2015a).…”

Section: A Historical Reviewmentioning

confidence: 99%

“…Nonlinear wave-wave couplings and wave-particle interactions for DAW excited by EPs are historically considered separately, for the sake of simplicity and clarity of the analysis. However, noting that the existence of the SAW continuous spectrum could lead to the excitation of short-wavelength modes via resonant mode conversion of longer scale-lengths excited by EPs, EPs could, then, act as mediators of cross-scale couplings (Zonca, 2008;Zonca and Chen, 2008) 13 and play a unique role in determining complex behavior in burning plasmas (cf. also Secs.…”

Section: A General Theoretical Approachmentioning

confidence: 99%

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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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“…Major consequences of enhanced losses are a decreased fusion efficiency and possible damage to in-vessel structures. It is therefore important to understand this phenomenon in present devices in order to limit, or possibly avoid, its deleterious effects in future fusion reactors [3]. A scenario of particular concern for ITER contemplates the coupling of multiple TAE resonances resulting from their overlap in phase space [4].…”

Section: Introductionmentioning

confidence: 99%

Non-linear dynamics of toroidicity-induced Alfvén eigenmodes on the National Spherical Torus Experiment

et al. 2011

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Abstract.The National Spherical Torus Experiment (NSTX, [M. Ono et al., Nucl. Fusion 40, 557 (2000)])routinely operates with neutral beam injection as the primary system for heating and current drive. The resulting fast ion population is super-Alfvénic, with velocities 1 < v f ast /v Alf ven < 5. This provides a strong drive for toroidicity-induced Alfvén eigenmodes (TAEs). As the discharge evolves, the fast ion population builds up and TAEs exhibit increasing bursts in amplitude and down-chirps in frequency, which eventually lead to a so-called TAE avalanche. Avalanches cause large ( 30%) fast ion losses over ∼ 1 ms, as inferred from the neutron rate. The increased fast ion losses correlate with a stronger activity in the TAE band. In addition, it is shown that a n = 1 mode with frequency well below the TAE gap appears in the Fourier spectrum of magnetic fluctuations as a result of non-linear mode coupling between TAEs during avalanche events. The non-linear coupling between modes, which leads to enhanced fast ion transport during avalanches, is investigated.

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Nonlinear Dynamics and Complex Behaviors in Magnetized Plasmas of Fusion Interest

Cited by 12 publications

References 57 publications

Analytic studies of dispersive properties of shear Alfvén and acoustic wave spectra in tokamaks

Analytic studies of dispersive properties of shear Alfvén and acoustic wave spectra in tokamaks

Physics of Alfvén waves and energetic particles in burning plasmas

Non-linear dynamics of toroidicity-induced Alfvén eigenmodes on the National Spherical Torus Experiment

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