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	160: Dependence of confinement and stability on toroidal rotation in high li discharges
Name:	John Ferron ferron@fusion.gat.com	Affiliation:	General Atomics
Research Area:	Steady State Heating and Current Drive	Presentation time:	Not requested
Co-Author(s):		ITPA Joint Experiment :	No
Description:	Produce a high li discharge that runs without beta collapse at significant betaN (for example, about 4). Evaluate the dependence of confinement on toroidal rotation. Evaluate the effect of the toroidal rotation velocity on the stability limit, both the maximum attainable betaN and the no-wall limit as measured with MHD spectroscopy.	ITER IO Urgent Research Task :	No
Experimental Approach/Plan:	Produce a high betaN discharge similar to those produced in 2008. Add counter injection beams. In order to reduce the rotation to low values, it will probably be necessary to operate at less than the maximum betaN.
Background:	The normalized confinement in high li discharges seems to increase as the beam power increases, possibly indicating a dependence of confinement on toroidal rotation velocity. On the other hand, experiments in the 1990s also indicated that the enhanced confinement at higher li depends on the poloidal field strength profile. It is essential to understand the confinement at high li under low rotation conditions as might be expected in a reactor. Also, a motivation for the high li scenario is that high betaN can be obtained in the absence of wall stabilization. The stability at low rotation in DIII-D discharges should be tested to determine the role of the wall in stabilization. Discharges in 2008 had phases with betaN below the no-wall limit and phases with betaN above the limit.
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