Scaling properties of turbulence driven shear flow

Yan, Z.; Tynan, G. R.; Holland, C.; Xu, M.; Muller, S. H.; Yu, J. H.
January 2010
Physics of Plasmas;Jan2010, Vol. 17 Issue 1, p012302
Academic Journal
The characteristics and scaling properties of the turbulence driven shear flow are investigated in a cylindrical laboratory plasma device. For a given plasma pressure, the density fluctuation amplitude and radial particle flux increase with the applied magnetic field. Strong flow shear is found to coexist at high magnetic fields (>700 G) with ∼10 kHz drift wave turbulence, but not at low magnetic fields (<700 G). The absolute value of the divergence of the turbulent Reynolds stress at the shear layer is shown to increase with the magnetic field as well. For a fixed magnetic field, the shear flow is found to decrease as the discharge gas pressure is increased. The density fluctuation amplitude and divergence of the turbulent Reynolds stress also decrease with the plasma pressure. For both situations the cross phase between the radial and azimuthal components of the velocity is found to be a key factor to determine variations in the turbulent Reynolds stress at different magnetic fields and discharge pressures. The results show that the generation of the shear flow is related to the development of specific frequency components of the drift wave turbulence for a variety of plasma conditions. The linear stability analysis shows that the observed variation in the turbulence and shear flow with magnetic field is also consistent with a critical gradient behavior.


Related Articles

  • Low to high confinement transition theory of finite-beta drift-wave driven shear flow and its comparison with data from DIII-D. Guzdar, P.N.; Kleva, R.G.; Groebner, R.J.; Gohil, P. // Physics of Plasmas;Mar2004, Vol. 11 Issue 3, p1109 

    Shear flow stabilization of edge turbulence in tokamaks has been the accepted paradigm for the improvement in confinement observed in high (H) confinement mode plasmas. Results on the generation of zonal flow and fields in finite β plasmas are presented. This theory yields a criterion for...

  • Loss of confinement at the density limit due to the suppression of stabilizing zonal flows by magnetic turbulence. Kleva, Robert G.; Guzdar, Parvez N. // Physics of Plasmas;Aug2008, Vol. 15 Issue 8, p082307 

    The character of particle and energy transport in numerical simulations of drift-ballooning turbulence changes dramatically as the density exceeds a critical limit. When the density is not too large, then unstable drift-ballooning fluctuations grow and nonlinearly generate a sheared zonal (flux...

  • Low-beta equilibrium and stability for anisotropic pressure closed field line plasma confinement... Pastukhov, V.P.; IIgisonis, V.I.; Subbotin, A.A. // Physics of Plasmas;Feb96, Vol. 3 Issue 2, p536 

    Develops a formalism to analyze the equilibrium and stability of low-beta anisotropic pressure plasma confined in closed field line magnetic systems. Self-consistent equilibrium and stability consideration of rather general magnetic systems with nonuniform axis curvature and longitudinal...

  • Nonlinear dust Alfve´n waves in plasmas with shear flow. Haque, Q.; Saleem, H. // Physics of Plasmas;Aug2002, Vol. 9 Issue 8, p3633 

    In the presence of a nonuniform magnetic field and shear flow, two coupled nonlinear equations for perturbed electromagnetic fields are derived in a dusty plasma. A linear instability of dust Alfvén waves is discussed and the analytical solution of the nonlinear equations is found in the form...

  • Flow shear induced fluctuation suppression in finite aspect ratio shaped tokamak plasma. Hahm, T. S.; Burrell, K. H. // Physics of Plasmas;May95, Vol. 2 Issue 5, p1648 

    Studies the suppression of turbulence by the ExB flow shear and parallel flow shear in an arbitrary shape finite aspect ratio tokamak plasma using the two point nonlinear analysis previously utilized in high aspect ratio tokamak plasma. Role of the ExB flow shear in the suppression of...

  • Beyond paradigm: Turbulence, transport, and the origin of the radial electric field in low to... Moyer, R.A.; Burrell, K.H.; Carlstrom, T.N.; Coda, S.; Conn, R.W.; Doyle, E.J.; Gohil, P.; Groebner, R.J.; Kim, J.; Lehmer, R.; Peebles, W.A.; Porkolab, M.; Rettig, C.L.; Rhodes, T.L.; Seraydarian, R.P.; Stockdale, R.; Thomas, D.M.; Tynan, G.R.; Watkins, J.G. // Physics of Plasmas;Jun95, Vol. 2 Issue 6, p2397 

    Examines the paradigm of shear suppression of turbulence as the mechanism for the low to high (L to H) confinement mode transition, by quantitative comparison of the predictions of the paradigm with experimental results from the DIII-D tokamak. Triggering of a VxB rotation due to the L to H...

  • The effect of sheared diamagnetic flow on turbulent structures generated by the Charney--Hasegawa... Botha, G. J. J.; Haines, M. G.; Hastie, R.J. // Physics of Plasmas;Oct99, Vol. 6 Issue 10, p3838 

    Examines the effect of a sheared diamagnetic flow on turbulent structures generated by the Charney-Hasegawa-Mima equation. Short review of numerical simulations which used the CHM equation; Coherent structure in the plasma which form in the turbulence; Spectra formed by the generalized energy...

  • On the nonlinear turbulent dynamics of shear-flow decorrelation and zonal flow generation. Tynan, G. R.; Moyer, R. A.; Burin, M. J.; Holland, C. // Physics of Plasmas;Jun2001, Vol. 8 Issue 6, p2691 

    Sheared flows, thought to be generated by turbulence in magnetized fusion plasmas, are predicted to mediate the transport of mass, momentum, and heat across the shear flow region. In this paper we show that an examination of three-wave coupling processes using the bispectrum and bicoherence of...

  • Effects of magnetic geometry, fluctuations, and electric fields on confinement in the Advanced Toroidal Facility. Isler, R. C.; Aceto, S.; Baylor, L. R.; Bigelow, T. S.; Bell, G. L.; Bell, J. D.; Carreras, B. A.; Colchin, R. J.; Crume, E. C.; Dominguez, N.; Dory, R. A.; Dunlap, J. L.; Dyer, G. R.; England, A. C.; Gandy, R. F.; Glowienka, J. C.; Hanson, G. R.; Harris, J. H.; Hiroe, S. // Physics of Fluids B: Plasma Physics;Jul92, Vol. 4 Issue 7, p2104 

    Recent experiments in the Advanced Toroidal Facility (ATF) [Fusion Technol. 10, 179 (1986)] have been directed toward investigations of the basic physics mechanisms that control confinement in this device. Measurements of the density fluctuations throughout the plasma volume have provided...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics