Scaling law: Difference between revisions

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When α = 0, the scaling is said to be of the Bohm type, and when α = 1, of the gyro-Bohm type.
When α = 0, the scaling is said to be of the Bohm type, and when α = 1, of the gyro-Bohm type.


The L-mode scaling is of the Bohm type, while the ELMy H-mode scaling is of the gyro-Bohm type.
The ELMy H-mode scaling is of the gyro-Bohm type.
Gyro-Bohm scaling is what one would expect for diffusive transport based on a diffusive scale length proportional to &rho;<sub>i</sub> (the ion gyroradius). Bohm scaling, however, suggests that transport may [[Non-diffusive transport|not be diffusive]] and not characterized by a typical scale length, i.e., is dominated by the scale length corresponding to the machine size (non-locality).  
Gyro-Bohm scaling is what one would expect for diffusive transport based on a diffusive scale length proportional to &rho;<sub>i</sub> (the ion gyroradius).
 
By contrast, the L-mode scaling is of the Bohm type, which suggests that transport may [[Non-diffusive transport|not be diffusive]] and not characterized by a typical scale length, i.e., it is dominated by the scale length corresponding to the machine size (non-locality).  
<ref>A. Dinklage, ''Plasma physics: confinement, transport and collective effects'', Vol. 670 of Lecture notes in physics, Springer (2005) ISBN 3540252746</ref>
<ref>A. Dinklage, ''Plasma physics: confinement, transport and collective effects'', Vol. 670 of Lecture notes in physics, Springer (2005) ISBN 3540252746</ref>
One possible explanation of this behaviour is [[Self-Organised Criticality]], i.e., the self-regulation of transport by turbulence, triggered when a critical value of the gradient is exceeded. As a corollary, this mechanism might also explain the phenomenon of profile consistency.


== References ==
== References ==
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