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Title	117: Conditions for nonlinear Alfvén Eigenmode evolution and impact on fast ion confinement and loss
Name:	Alberto Loarte-Prieto Alberto.Loarte@iter.org	Affiliation:	ITER Organization
Research Area:	Energetic Particles	Presentation time:	Requested
Co-Author(s):	S Pinches, WW Heidbrink, SE Sharapov	ITPA Joint Experiment :	Yes
Description:	The aim of this experiment is to: (1) Experimentally establish the criteria for the transition from steady-state, constant frequency, Alfvén Eigenmode activity to nonlinear behaviour in which the frequency and amplitude rapidly change (e.g. as seen in chirping events); and (2) Quantify the impact on fast ion confinement and/or losses that results from this change in behaviour.	ITER IO Urgent Research Task :	Yes
Experimental Approach/Plan:	Select reference case in which NBI driven AE are observed to behave nonlinearly. (This will probably be a low-field case (Bt < 1.4 T) such that the beam ions are super-Alfvénic.) Scan in toroidal magnetic field and/or plasma density (and possibly electron temperature using ECRH) to change collisionality at the resonant velocity and transition between types of nonlinear behaviour, and observe effects upon fast ion population.
Background:
Resource Requirements:	NBI heating system.
Diagnostic Requirements:	Fast ion diagnostics (FIDA, FILD, NPA, neutrons), instability diagnostics (magnetics, SXR, ECEI), equilibrium diagnostics (core profiles including MSE).
Analysis Requirements:	Equilibrium reconstruction; Magnetics analysis (toroidal mode number and frequency evolution); Nonlinear fast ion codes that can be validated against these results and used to predict behaviour in ITER.
Other Requirements: