Prediction of Nonlinear Evolution Character of Energetic-Particle-Driven Instabilities

Abstract

A general criterion is proposed and found to successfully predict the emergence of chirping oscillations of unstable Alfvénic eigenmodes in tokamak plasma experiments. The model includes realistic eigenfunction structure, detailed phase-space dependences of the instability drive, stochastic scattering and the Coulomb drag. The stochastic scattering combines the effects of collisional pitch angle scattering and micro-turbulence spatial diffusion. The latter mechanism is essential to accurately identify the transition between the fixed-frequency mode behavior and rapid chirping in tokamaks and to resolve the disparity with respect to chirping observation in spherical and conventional tokamaks.

References in corpus (1)

• Experimental investigation of the radial structure of energetic particle driven modes

Cited by in corpus (13)

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• Onset of nonlinear structures due to eigenmode destabilization in tokamak plasmas
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• Resonance frequency broadening of wave-particle interaction in tokamaks due to Alfvénic eigenmode
• The collisional resonance function in discrete-resonance quasilinear plasma systems
• Analytical nonlinear collisional dynamics of near-threshold eigenmodes
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• Analytic quasi-steady evolution of a marginally unstable wave in the presence of drag and scattering
• Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability