Generation of parasitic axial flow by drift wave turbulence with broken symmetry: Theory and experiment
| Autor: | R. J. Hajjar, J. Li, George Tynan, R. Hong, S. Chakraborty Thakur, Patrick Diamond |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Density gradient Turbulence Wave turbulence media_common.quotation_subject FOS: Physical sciences Mechanics Reynolds stress Condensed Matter Physics 01 natural sciences Asymmetry Physics - Plasma Physics 010305 fluids & plasmas Magnetic field Plasma Physics (physics.plasm-ph) Physics::Fluid Dynamics Axial compressor 0103 physical sciences Mean flow 010306 general physics media_common |
| Zdroj: | Physics of Plasmas. 25:055710 |
| ISSN: | 1089-7674 1070-664X |
| DOI: | 10.1063/1.5017884 |
| Popis: | Detailed measurements of intrinsic axial flow generation parallel to the magnetic field in the controlled shear decorrelation experiment linear plasma device with no axial momentum input are presented and compared to theory. The results show a causal link from the density gradient to drift-wave turbulence with broken spectral symmetry and development of the axial mean parallel flow. As the density gradient steepens, the axial and azimuthal Reynolds stresses increase and radially sheared azimuthal and axial mean flows develop. A turbulent axial momentum balance analysis shows that the axial Reynolds stress drives the radially sheared axial mean flow. The turbulent drive (Reynolds power) for the azimuthal flow is an order of magnitude greater than that for axial flow, suggesting that the turbulence fluctuation levels are set by azimuthal flow shear regulation. The direct energy exchange between axial and azimuthal mean flows is shown to be insignificant. Therefore, the axial flow is parasitic to the turbulence-zonal flow system and is driven primarily by the axial turbulent stress generated by that system. The non-diffusive, residual part of the axial Reynolds stress is found to be proportional to the density gradient and is formed due to dynamical asymmetry in the drift-wave turbulence.Detailed measurements of intrinsic axial flow generation parallel to the magnetic field in the controlled shear decorrelation experiment linear plasma device with no axial momentum input are presented and compared to theory. The results show a causal link from the density gradient to drift-wave turbulence with broken spectral symmetry and development of the axial mean parallel flow. As the density gradient steepens, the axial and azimuthal Reynolds stresses increase and radially sheared azimuthal and axial mean flows develop. A turbulent axial momentum balance analysis shows that the axial Reynolds stress drives the radially sheared axial mean flow. The turbulent drive (Reynolds power) for the azimuthal flow is an order of magnitude greater than that for axial flow, suggesting that the turbulence fluctuation levels are set by azimuthal flow shear regulation. The direct energy exchange between axial and azimuthal mean flows is shown to be insignificant. Therefore, the axial flow is parasitic to the turbule... |
| Databáze: | OpenAIRE |
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