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Scaling law: Difference between revisions
→Power degradation
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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. 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. | 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 (i.e., more than the expected -diffusive- increase due to the increased gradient alone), 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]]. | ||