Scaling law: Difference between revisions
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:<math>\tau_E \propto P^{-\alpha}</math> | :<math>\tau_E \propto P^{-\alpha}</math> | ||
where α has a value of 0.6 ± 0.1. The reason for this behaviour has not been fully clarified. | where α has a value of 0.6 ± 0.1. The reason for this behaviour has not been fully clarified. Qualitatively, it seems obvious that an increase of ''P'' will lead to an increase of (temperature and density) gradients, and thus an increase of "free energy" available to instabilities and turbulence. These instabilities may grow by feeding on the "free energy", which may lead to an increase of transport, producing the observed confinement degradation. | ||
This phenomenon is therefore a form of plasma [[Self-Organised Criticality|self-organisation]]. | This phenomenon is therefore a form of plasma [[Self-Organised Criticality|self-organisation]]. | ||
== Size scaling == | |||
The L-mode scaling is of the "Bohm" type, while the ELMy H-mode 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 ρ<sub>i</sub> (the ion gyroradius). "Bohm" scaling, however, suggests that transport is not diffusive and not characterized by a typical scale length. | |||
(''More detail needed'') | |||
== Dimensionless parameters == | == Dimensionless parameters == | ||