Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas

Journal Article · Tue Mar 01 00:00:00 EST 2016 · Plasma Physics and Controlled Fusion

DOI:https://doi.org/10.1088/0741-3335/58/4/045026· OSTI ID:1350091

Wang, Xin ^[1]; Mordijck, Saskia ^[1]; Zeng, Lei ^[2]; Schmitz, Lothar ^[2]; Rhodes, Terry L. ^[2]; Doyle, Edward J. ^[2]; Groebner, Richard ^[3]; Meneghini, Orso ^[3]; Staebler, George M. ^[3]; Smith, Sterling P. ^[3]

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1. College of William and Mary, Williamsburg, VA (United States)
2. Univ. of California, Los Angeles, CA (United States)
3. General Atomics, San Diego, CA (United States)

In this paper we show how changes in toroidal rotation, by controlling the injected torque, affect particle transport and confinement. The toroidal rotation is altered using the co- and counter neutral beam injection (NBI) in low collisionality H-mode plasmas on DIII-D with dominant electron cyclotron heating (ECH). We find that there is no correlation between the toroidal rotation shear and the inverse density gradient, which is observed on AUG when $${{T}_{\text{e}}}/{{T}_{\text{i}}}$$ is varied using ECH (Angioni et al 2011 Phys. Rev. Lett. 107 215003). In DIII-D, we find that in a discharge with balanced torque injection, the $$E\times B$$ shear is smaller than the linear gyrokinetic growth rate for small $${{k}_{\theta}}{{\rho}_{s}}$$ for $$\rho =0.6$$ –0.85. This results in lower particle confinement. In the co- and counter- injected discharges the $$E\times B$$ shear is larger or close to the linear growth rate at the plasma edge and both configurations have higher particle confinement. In order to measure particle transport, we use a small periodic perturbative gas puff. This gas puff perturbs the density profiles and allows us to extract the perturbed diffusion and inward pinch coefficients. We observe a strong increase in the inward particle pinch in the counter-torque injected plasma. Lastly, the calculated quasi-linear particle flux, nor the linear growth rates using TGLF agree with experimental observations.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FC02-04ER54698; FG02-08ER54984; SC0007880
• OSTI ID: 1350091
• Alternate ID(s): OSTI ID: 1239851
• Journal Information: Plasma Physics and Controlled Fusion, Vol. 58, Issue 4; ISSN 0741-3335
• Publisher: IOP Science
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
particle transport
ExB shear
turbulence