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Title 324: Dependence of non-resonant magnetic braking on nu_i and v_phi profile
Name:Steven A. Sabbagh () Affiliation:Columbia University
Research Area:Rotation Physics Presentation time: Requested
Co-Author(s): H. Reimerdes, A.M. Garofalo, W. Solomon
Description: Examine the dependence of ion collisionality and rotation profile on neoclassical toroidal viscosity theory (joint experiment with NSTX)
Experimental Approach/Plan: Create plasmas with weak or no low frequency rotating MHD modes (especially n = 1). Vary ion collisionality and rotation profile in relatively high stored energy plasmas. Change ion collisionality in most effective way for DIII-D, preferably (but not necessarily) at fixed q. Change rotation profile by changing NBI mix.
Operate at highest controllable elongation with good H-mode to best compare to NSTX.
Background: Research on NSTX over the past several years (e.g. S.A. Sabbagh, et al., PoP 5 (2002) 2085.) has identified broad radial braking of the plasma rotation profile during RWM activity and non-resonant applied fields with the theory of neoclassical toroidal viscosity (NTV). This correlation has also been recognized in JET, and magnetic braking has been used for many years in DIII-D. Experimental results have shown quantitative agreement with NTV theory when trapped particle effects are included (W. Zhu, et al., PRL 96 (2006) 225002.). Testing the saturation of the viscosity at low collisionality and the dependence on rotation profile shape is of particular importance to ITER. The experiment can be conducted in joint fashion with NSTX to best verify the theory (e.g. aspect ratio dependence ~ (1/A)^1.5).
Resource Requirements: Expect that full NBI power is needed, with maximum counter-NBI capability to best vary rotation profile.
Diagnostic Requirements: Toroidal rotation profile measurement, MSE measurements
Analysis Requirements: Most accurate EFIT reconstructions possible (Kinetic reconstructions with MSE, flux-isotherm constraint if available). First-principles calculation of NTV will be performed with equilibrium reconstructions as input.
Other Requirements: (present with other PPPL presentations)