DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
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Title	292: Optimize electron pedestal pressure in low-torque ITER baseline plasmas
Name:	Lothar Schmitz schmitzl@fusion.gat.com	Affiliation:	University of California, Los Angeles
Research Area:	Inductive Scenarios	Presentation time:	Not requested
Co-Author(s):	G. Jackson, T. Luce, W. Solomon, F. Turco, K.H. Burrell, E. Doyle, T.L. Rhodes, C. Holland	ITPA Joint Experiment :	No
Description:	Low torque ITER-similar discharges were successfully achieved in the 2012 campaign using a combination of ECH with NBI co- and counter-injection at low- or moderate power. Building on these achievements, this proposal seeks to optimize pedestal electron pressure to achieve a higher pedestal electron temperature and Te/Ti > 1 in the outer core plasma. Combined with a beam torque scan this will allow investigating the dependence of thermal and momentum transport on Te/Ti in the ITER-like shape while decreasing electron-ion collisional coupling to some extent. Increased counter beam torque can increase the pedestal ExB shear and width of the shear layer potentially improve the edge transport barrier/pedestal pressure.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Establish ITER-similar plasma with moderate co-NBI and full ECH power (Reference shot #150400). Improve pedestal Te by varying the beam torque (combined co/counter-injection), and scanning the ECH deposition location between r/a=0.25-0.5. Obtain detailed fluctuation measurements in the outer core plasma and pedestal, using BES, DBS and CECE (the latter will require blocking ELM events during analysis to increase sensitivity). Core DBS will be possible (using O-mode) if the outer core density gradient is not inverted or flat ( Increasing the density gradient in the outer core via deep fueling/pellet injection may be explored if it does not com promise the pedestal temperature).
Background:	In lower density QH-mode experiments withy ECH run in 2012 the achieved increment in Te and the pedestal top electron temperature with ECH were very sensitive to he ECH deposition radius. A strong dependence of the toroidal rotation profile on deposition location was also observed. Pedestal electron temperatures up to 3 keV were achieved. The present proposal seeks to explore to what extent the pedestal rotation profile, the outer core momentum transport, and the ration of electron to ion thermal transport can be tailored to improve pedestal pressure and Te/Ti at higher density in ITER-like (ElMing H-mode) plasmas
Resource Requirements:	All beams , ECH (6 gyrotrons), possibly pellet injection.
Diagnostic Requirements:
Analysis Requirements:	Transport analysis/TGLF/GYRO to assess instability growth rates; the ITG/TEM transition, and nonlinear turbulence evolution.
Other Requirements: