DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 268: Study of turbulence effects on anomalous particle and momentum pinches | ||
| Name: | Lei Zeng ( |
Affiliation: | University of California, Los Angeles |
| Research Area: | Transport | Presentation time: | Not requested | Co-Author(s): | E. J. Doyle, T. L. Rhodes, A.E. White, G. Wang, L. Schmitz, W.A. Peebles |
| Description: | In this experiment, we study the effects of core turbulence on anomalous particle and momentum pinches and transports, and the dependence of the pinches on collisionality. By comparing experimental data to theoretical models (GS2, GYRO and others), the mechanisms of anomalous pinch can be further studied. | ||
| Experimental Approach/Plan: | In RF heating plasma (without NBI core particle source), when scaning collisionality from low to high, measure Te and ne fluctuations in the core. Use modulated momentum and particle transport technique, to separately determine diffusion and pinch calculations (co/counter NBI blips can be used for momentum study). Also, by using impurity pellet injection or modulated He NBI, analyze particle transport. The measurements of ne, Te, q and rotation profile variations in the core (rho< 0.6) are needed.
Experimental data is used to compare with the simulations from GS2 and GYRO. | ||
| Background: | The understanding of the mechanisms of core particle and momentum transports is important for ITER and other fusion plasmas. Recently, the anomalous inward particle pinch has been observed in several tokamaks. The inward pinch velocity is much larger than the expected value via neoclassical theory. In Tore Supra, the ICRH heating during non-inductive LHCD experiment shows the inward pinch is driven by turbulent thermo-diffusion for rho<0.3, while the inward pinch is driven by turbulence equipartition for 0.3<rho<0.6. In AUG and JET experiments, it is observed that the density peaking increases with decreasing collisionality, consistent with the GS2 simulation. Currently, a novel momentum pinch mechanism is proposed by T.S. Hahm et al.
In DII-D, with the updated diagnostic measurements for turbulence and profiles, these mechanisms can be further tested and investigated. We will study the dependence of anomalous pinch on collisionality, the effects of ne fluctuations from low to high k, and Te fluctuation. Comparison between experimental results and simulation results from GS2, GYRO and others will also be proceeded. | ||
| Resource Requirements: | Fast wave heating, ECH | ||
| Diagnostic Requirements: | FIR, CECE, reflectometers , BES | ||
| Analysis Requirements: | GS2, GYRO | ||
| Other Requirements: | -- | ||
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