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	35: Non-Diffusive Heat Fluxes in the Edge "Shortfall" Region
Name:	Clinton (Craig) Petty petty@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Turbulence & Transport	Presentation time:	Not requested
Co-Author(s):	T. Luce, S. Smith, C. Holland	ITPA Joint Experiment :	No
Description:	Determine whether the "shortfall" by turbulent transport models in the edge heat flux for L-mode plasmas is due to an under prediction of the non-diffusive heat flux. The diffusive and non-diffusive heat fluxes will be measured in two locations: first, in the edge "shortfall" region; second, near the half-radius where transport codes do a better job of predicting the heat flux. The electron critical gradient, electron transport stiffness and fluxes will be determined from (1) by measuring the power balance and heat pulse transport, and (2) from the turbulence behavior (for the critical gradient). This proposal is essentially the same as #34 except the plasma conditions are more similar to the 2011 DeBoo experiment (higher current, lower density than for #34).	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	(1) Use plasma condition for which a well established "shortfall" exists in the edge heat flux predicted by transport models. (2) Inject all gyrotrons at rho=0.8. with one gyrotron modulated at 25 Hz. (3) Shot to shot, move one gyrotron to rho=0.6 and measure change in electron temperature gradient and heat pulse propagation. (4) Document turbulence behavior during these discharges using CECE, DBS, etc. (5) Repeat all steps but with ECH moved to rho=0.6 and rho=0.4. (6) Can add a late beam-heated phase to all cases to measure BES and rotational effects.
Background:	It has been well established that in many L-mode plasmas, transport models such as TGLF and GYRO drastically under predict the ion and electron heat fluxes in the outer regions. This "shortfall" causes the transport simulations to essentially fail in the edge region. This experiment will determine if this theory/experiment disagreement is due to theory under predicting the effect of non-diffusive heat flux; the experiment will also measure the critical gradient and stiffness in the conductive electron heat flux, which may provide additional clues as to the origin of the disagreement.
Resource Requirements:	ECH: 6 gyrotrons desired. NBI: 30LT and 330LT beams essential, 150LT desired.
Diagnostic Requirements:	All fluctuation diagnostics are required.
Analysis Requirements:	Transport analysis with ONETWO and poetAP. Turbulence and transport modeling with TGLF and GYRO.
Other Requirements:	--