Sensitivity of alpha-particle-driven Alfven eigenmodes to q-profile variation in ITER scenarios

Abstract

A perturbative hybrid ideal-MHD/drift-kinetic approach to assess the stability of alpha-particle-driven Alfven eigenmodes in burning plasmas is used to show that certain foreseen ITER scenarios, namely the Ip = 15 MA baseline scenario with very low and broad core magnetic shear, are sensitive to small changes in the background magnetic equilibrium. Slight variations (of the order of 1%) of the safety-factor value on axis are seen to cause large changes in the growth rate, toroidal mode number, and radial location of the most unstable eigenmodes found. The observed sensitivity is shown to proceed from the very low magnetic shear values attained throughout the plasma core, raising issues about reliable predictions of alpha-particle transport in burning plasmas.

arXiv comment10 pages, 4 figures; Accepted manuscript

References in corpus (3)

• Nonlinear stabilization of tokamak microturbulence by fast ions
• Energetic particle instabilities in fusion plasmas
• Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

Cited by in corpus (6)

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• Drift kinetic theory of alpha transport by tokamak perturbations
• Study of the likelihood of Alfvénic mode bifurcation in NSTX and predictions for ITER baseline scenarios
• Dependence of alpha-particle-driven Alfvén eigenmode linear stability on device magnetic field strength and consequences for next-generation tokamaks
• Assessing the Numerical Stability of Physics Models to Equilibrium Variation through Database Comparisons