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Title 52: Control of TAE/RSAE modes via external perturbations
Name:Mario Podesta mpodesta@pppl.gov Affiliation:Princeton Plasma Physics Laboratory
Research Area:Energetic Particles Presentation time: Not requested
Co-Author(s): DIII-D EP group ITPA Joint Experiment : No
Description: Explore the possibility of affecting the TAE/RSAE dynamics by means of externally applied, low-n perturbations. ITER IO Urgent Research Task : No
Experimental Approach/Plan: Reproduce plasmas with robust TAE/RSAE activity. Better if TAEs appear as 'cluster' of modes with comparable frequency. Aim at low rotation discharges so that the Doppler shift of TAE frequencies is small and can be matched by the Internal Coils. Perform amplitude and frequency scans of n=1 perturbations imposed through the Internal Coils and characterize modifications of AE dynamics. Focus on startup phase, possibly w/ balanced NBI to avoid fast plasma rotation.
Background: Low-frequency MHD modes have been observed to couple with TAE modes through three-wave coupling (DIII-D, NSTX). The proposed experiment is aimed at inducing a similar coupling between pairs of TAE (and, possibly, RSAE) modes and externally applied perturbations. If entanglement of the TAEs is observed, a parametric study of the amplitude/frequency of the external perturbation will reveal the threshold for effective coupling and the feasibility of this method to regulate the dynamic of bursting/chirping Alfvénic modes which are responsible for fast ion loss and redistribution.
Resource Requirements: Internal coils operating at relatively high frequency (~1 kHz), n=1 configuration.
Diagnostic Requirements: All fast ion diagnostics, ECEI, possibly reflectometers. Profile diagnostics (TS, CER, MSE).
Analysis Requirements: EFIT, TRANSP, NOVA
Other Requirements: