DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 289: Main ion poloidal rotation measurements in helium plasmas | ||
| Name: | Keith Burrell ( |
Affiliation: | General Atomics |
| Research Area: | Rotation Physics | Presentation time: | Not requested | Co-Author(s): | J.S. DeGrassie, W.M. Solomon |
| Description: | The goal of this experiment is to test the neoclassical theory of poloidal rotation by measuring the rotation of the main (helium) and impurity (carbon) ions under a variety of conditions. These will be in Ohmic, ECH and NBI H-modes. | ||
| Experimental Approach/Plan: | These experiments will build on the ECH H-mode developed in helium plasmas during the 2003 and 2004 campaigns. In addition, they will utilize the ability of the CER system to make high time resolution measurements of the plasma rotation just after beam turn on. This allows us to use the beams to make the measurement before they have had time to alter the rotation. Using combinations of ECH and beams, we will make L-mode and H-mode plasmas, some totally RF dominated and others beam dominated. The beam dominated shots will cover cases with significant co-injection, balanced injection and counter injection. | ||
| Background: | Because of its role in affecting E x B shear stabilization of turbulence, developing a predictive understanding of plasma rotation is an essential part of transport studies. Measurements in 2004-2005 presented by W. Solomon at the 2005 APS DPP meeting showed that the impurity poloidal rotation did not agree with neoclassical predictions in QH-mode and RMP ELM-suppressed H-mode plasmas. However, to date, there has not been a good test of the theoretical predictions for the main ion rotation. One possible explanation for the discrepancy seen by Solomon et al is the effect of friction with the neutral beam ions. Performing experiments both with and without NBI will allow us to investigate this possibility. In addition, having measurements of the main and impurity ions allows provides significantly more information, since the coupling to the fast ions is different. During the LTOA, we installed a improved detectors for the poloidal views for the CER system; we are now in a position to make much better measurements of poloidal rotation. | ||
| Resource Requirements: | 4 gyrotrons. CER beams plus 2 more | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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