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Internal Transport Barrier: Difference between revisions
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== Physical mechanism == | == Physical mechanism == | ||
The mechanism for the formation of Internal Transport Barriers in magnetically confined plasmas is complex and not fully understood. | The mechanism for the formation of Internal Transport Barriers in magnetically confined plasmas is complex and not fully understood. | ||
The general consensus is that ITBs are the consequence of turbulence suppression due to sheared (''E'' × ''B'') flows. | |||
<ref>[http://link.aip.org/link/?PHPAEN/4/1499/1 K.H. Burrell, ''Effects of E × B velocity shear and magnetic shear on turbulence and transport in magnetic confinement devices'', Phys. Plasmas '''4''' (1997) 1499]</ref> | <ref>[http://link.aip.org/link/?PHPAEN/4/1499/1 K.H. Burrell, ''Effects of E × B velocity shear and magnetic shear on turbulence and transport in magnetic confinement devices'', Phys. Plasmas '''4''' (1997) 1499]</ref> | ||
This mechanism is evidently related to the mechanism for the formation of the [[H-mode]] barrier. | |||
ITBs are often found to be associated with rational magnetic surfaces. | ITBs are often found to be associated with rational magnetic surfaces. | ||
Factors contributing to the formation of ITBs include: | Factors contributing to the formation of ITBs include: | ||
<ref>[http://dx.doi.org/10.1088/0029-5515/44/4/R01 J.W. Connor et al, ''A review of internal transport barrier physics for steady-state operation of tokamaks'', Nucl. Fusion '''44''' (2004) R1-R49]</ref> | <ref>[http://dx.doi.org/10.1088/0029-5515/44/4/R01 J.W. Connor et al, ''A review of internal transport barrier physics for steady-state operation of tokamaks'', Nucl. Fusion '''44''' (2004) R1-R49]</ref> | ||
* | * The power deposited inside the [[Flux surface|magnetic surface]], and/or local pressure gradients | ||
* [[Magnetic shear]] and the shape of the rotational transform profile | * [[Magnetic shear]] and the shape of the rotational transform profile (e.g., reversed shear) | ||
* MHD activity | * MHD activity | ||
* Momentum torques (poloidal or toroidal) | * Momentum torques (poloidal or toroidal) | ||