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TJ-II:Confinement transitions: Difference between revisions
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Strongly driven fusion-grade plasmas often develop spontaneous (radial) narrow zones with steep gradients. This spontaneous local improvement of confinement is of fundamental importance for the operation of fusion plasmas. In fact, the important H-mode depends on it. | Strongly driven fusion-grade plasmas often develop spontaneous (radial) narrow zones with steep gradients. This spontaneous local improvement of confinement is of fundamental importance for the operation of fusion plasmas. In fact, the important H-mode | ||
<ref>[ttp://link.aps.org/doi/10.1103/PhysRevLett.53.1453 F. Wagner et al, ''Development of an Edge Transport Barrier at the H-Mode Transition of ASDEX'', Phys. Rev. Lett. '''53''' (1984) 1453 - 1456]</ref> | |||
depends on it. | |||
While this phenomenon is still not completely understood, much progress has been made in recent years. It is believed that turbulent fluctuations drive sheared or zonal flows via the Reynolds Stress Mechanism. This flow then shears the turbulent eddies apart, leading to local turbulence suppression at specific radial locations, and a concomitant local reduction of transport. | While this phenomenon is still not completely understood, much progress has been made in recent years. It is believed that turbulent fluctuations drive sheared or zonal flows via the Reynolds Stress Mechanism. This flow then shears the turbulent eddies apart, leading to local turbulence suppression at specific radial locations, and a concomitant local reduction of transport. | ||
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<ref>[http://link.aps.org/doi/10.1103/PhysRevLett.91.065001 C. Hidalgo et al, ''Experimental Investigation of Dynamical Coupling between Turbulent Transport and Parallel Flows in the JET Plasma-Boundary Region'', Phys. Rev. Lett. '''91''' (2003) 065001]</ref> | <ref>[http://link.aps.org/doi/10.1103/PhysRevLett.91.065001 C. Hidalgo et al, ''Experimental Investigation of Dynamical Coupling between Turbulent Transport and Parallel Flows in the JET Plasma-Boundary Region'', Phys. Rev. Lett. '''91''' (2003) 065001]</ref> | ||
<ref>[http://link.aps.org/doi/10.1103/PhysRevE.70.067402 C. Hidalgo et al., ''Experimental evidence of coupling between sheared-flow development and an increase in the level of turbulence in the TJ-II stellarator'', Phys. Rev. E '''70''' (2004) 067402]</ref> | <ref>[http://link.aps.org/doi/10.1103/PhysRevE.70.067402 C. Hidalgo et al., ''Experimental evidence of coupling between sheared-flow development and an increase in the level of turbulence in the TJ-II stellarator'', Phys. Rev. E '''70''' (2004) 067402]</ref> | ||
<ref>[http://dx.doi.org/10.1088/0741-3335/47/6/004 M.A. Pedrosa et al., Threshold for sheared flow and turbulence development in the TJ-II stellarator, Plasma Phys. Control. Fusion '''47''' (2005) 777-788 ]</ref> | <ref>[http://dx.doi.org/10.1088/0741-3335/47/6/004 M.A. Pedrosa et al., ''Threshold for sheared flow and turbulence development in the TJ-II stellarator'', Plasma Phys. Control. Fusion '''47''' (2005) 777-788 ]</ref> | ||
<ref>[http://dx.doi.org/10.1016/j.jnucmat.2004.10.067 E. Sánchez et al., ''On the energy transfer between flows and turbulence in the plasma boundary of fusion devices'', J. of Nuclear Materials '''337''' (2005) 296]</ref> | <ref>[http://dx.doi.org/10.1016/j.jnucmat.2004.10.067 E. Sánchez et al., ''On the energy transfer between flows and turbulence in the plasma boundary of fusion devices'', J. of Nuclear Materials '''337''' (2005) 296]</ref> | ||
<ref>[http://link.aip.org/link/?PHPAEN/13/122509/1 B.A. Carreras et al, ''Critical transition for the edge shear layer formation: Comparison of model and experiment'', Phys. Plasmas '''13''' (2006) 122509]</ref> | <ref>[http://link.aip.org/link/?PHPAEN/13/122509/1 B.A. Carreras et al, ''Critical transition for the edge shear layer formation: Comparison of model and experiment'', Phys. Plasmas '''13''' (2006) 122509]</ref> | ||