DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2013 EXPERIMENTAL CAMPAIGN Review | Direct submission with log-in | Request submission without log-in
Print this page

Print this page
Title	196: Narrow heat flux widths and divertor power dissipation
Name:	Anthony Leonard leonard@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Divertor & SOL Physics	Presentation time:	Requested
Co-Author(s):	--	ITPA Joint Experiment :	Yes
Description:	The goal is to determine the required conditions for partial detachment as a function of q_parallel and possible limits to lambda_q and/or upstream density associated with the MHD stability of the SOL.	ITER IO Urgent Research Task :	Yes
Experimental Approach/Plan:	Plasma shape and q95 will be similar to the ITER baseline inductive scenario. A power scan from P_inj/P_LH of 1.5 to maximum power will be carried out. At each power level a density scan to partial detachment of the outer divertor and ultimately to the H-mode density limit. High quality profiles of upstream, midplane, pedestal and separatrix values of density, temperature and pressure will be key measurements. Divertor measurements of heat flux from IR cameras as well as divertor plasma measurements should also be made. Key issues to be addressed by the analysis include 1) divertor heat flux width and its spreading with increased dissipation, 2) upstream/downstream pressure and power balance, 3) the upstream separatrix density at detachment, and its relationship to the Greenwald density limit, and 4) variation of the upstream pressure gradient and its relationship to the MHD stability parameter.
Background:	A multi-machine scaling study involving 6 tokamaks conducted by the ITPA, yielded a scaling of the inter-ELM H-mode near-SOL characteristic heat flux widths, which extrapolates to a midplane 1 mm SOL width for the ITER baseline inductive scenario. An extremely narrow power width in ITER implies very high upstream parallel heat fluxes which may be challenging to dissipate in the ITER divertor whilst maintaining a reasonable H-mode operational window. The scaling has so far concentrated on strongly attached divertor plasmas, but must now be extended to more directly ITER-relevant dissipative divertor conditions.
Resource Requirements:	All available beam power
Diagnostic Requirements:	Core and divertor Thomson scattering, IR camera and divertor Langmuir probes.
Analysis Requirements:	Edge stability analysis
Other Requirements:	--