On the correlation between ‘non-local’ effects and intrinsic rotation reversals in Alcator C-Mod

Journal Article · Wed May 17 00:00:00 EDT 2017 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aa6e89· OSTI ID:1535588

Rodriguez-Fernandez, P. ^[1]; Rice, J. E. ^[2]; Cao, N. M. ^[2]; Creely, A. J. ^[2]; Howard, N. T. ^[2]; Hubbard, A. E. ^[2]; Irby, J. H. ^[2]; White, A. E. ^[2]

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1. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; OSTI
2. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center

Contemporary predictive models for heat and particle transport in tokamak plasmas are based on the assumption that local fluxes can be described in terms of local plasma parameters, where electromagnetic drift-wave-type turbulence is driven by local gradients and results in cross-field transport. The question of whether or not transport could be dominated by non-local terms in certain circumstances is essential for our understanding of transport in magnetically confined plasmas, and critical for developing predictive models for future tokamaks, such as ITER. Perturbative transport experiments using cold-pulse injections at low density seem to challenge the local closure of anomalous transport: a rapid temperature increase in the core of the plasma following a sharp edge cooling is widely observed in tokamaks and helical devices. Past work in Ohmic plasmas in Alcator C-Mod and in ECH plasmas in KSTAR found that the temperature inversions disappear at higher densities, above the intrinsic toroidal rotation reversal density. These observations suggested that the so-called 'non-local' heat transport effects were related to the intrinsic rotation reversal, and therefore to changes in momentum transport. In this work, new experiments and analysis at Alcator C-Mod show that intrinsic rotation reversals and disappearance of temperature inversions are not concomitant in Ohmic plasmas at high plasma current and in ICRH L-modes. This new data set shows that the correlation between transient temperature inversions and intrinsic rotation reversals is not universal, suggesting that 'non-local' heat transport and momentum transport effects may be affected by different physical mechanisms.

• Research Organization: General Atomics, San Diego, CA (United States); Massachusetts Institute of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: La Caixa Fellowship; USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: FC02-04ER54698; FC02-99ER54512
• OSTI ID: 1535588
• Alternate ID(s): OSTI ID: 22925777
• Report Number(s): NF-101687.R1
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 7 Vol. 57; ISSN 0029-5515
• Publisher: IOP Science
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY