Simulation of RSAE/EAE and TAE activity in a reversed shear DIII-D case

POSTER

Abstract

The energetic particle gyrofuild model TAEFL has been applied to a DIII-D case where RSAE, TAE and EAE activity was present. This is a useful analysis tool because: (1) it retains the primary non-perturbative affect of fast ions on Alv\'{e}nic mode structures, i.e., the coupling of MHD cosine and sine parities by fast ion diamagnetic flows [which in the phi = 0 plane causes up-down asymmetries], (2) it is applicable to non-circular shaped tokamak equilibria, (3) it focuses on only the most unstable modes, and (4) an efficient implicit stepping algorithm has been developed, allowing rapid scans of linear growth rates and mode structures for cases with significant poloidal coupling. Analysis of the above DIII-D case has identified EAE, RSAE and TAE modes at sub-Alfv\'{e}nic beam velocities (down to $\sim $0.28 times the Alfv\'{e}n velocity). The dominant AE mode is a sensitive function of the q-profile and fast ion parameters. Also, the non-perturbative nature of this model yields mode structures that are consistent with the experimental coherence measurements.

Authors

  • D.A. Spong

    Oak Ridge National Lab., Oak Ridge National Laboratory

  • M.A. Van Zeeland

    GA, General Atomics