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TJ-II:Confinement transitions: Difference between revisions
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This mechanism may also underlie the formation of [[TJ-II:Internal Transport Barriers|internal transport barriers]]. | This mechanism may also underlie the formation of [[TJ-II:Internal Transport Barriers|internal transport barriers]]. | ||
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 mechanism transfers energy of high-frequency drift type turbulence to low wavelength modes. The zonal flow itself is radially localized and has a very long (infinite) toroidal and poloidal wavelength. 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. | ||
<ref>[http://dx.doi.org/10.1088/0741-3335/43/10/308 S.B. Korsholm et al, ''Reynolds stress and shear flow generation'', Plasma Phys. Control. Fusion '''43''' (2001) 1377-1395]</ref> | |||
This mechanism transfers energy of high-frequency drift type turbulence to low wavelength modes. The zonal flow itself is radially localized and has a very long (infinite) toroidal and poloidal wavelength. This flow then shears the turbulent eddies apart, leading to local turbulence suppression at specific radial locations, and a concomitant local reduction of transport. | |||
<ref>[http://dx.doi.org/10.1088/0741-3335/47/5/R01 P.H. Diamond et al, ''Zonal flows in plasma - a review'', Plasma Phys. Control. Fusion '''47''' (2005) R35-R161]</ref> | <ref>[http://dx.doi.org/10.1088/0741-3335/47/5/R01 P.H. Diamond et al, ''Zonal flows in plasma - a review'', Plasma Phys. Control. Fusion '''47''' (2005) R35-R161]</ref> | ||