Self-Organised Criticality: Difference between revisions

Self-Organised Criticality (view source)

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 Power degradation shows up in global transport scaling laws, and implies a sub-linear scaling of the plasma energy content with the injected power.
-The basic explanation for this phenomenon is self-regulation of the profiles by turbulence. The strong temperature and density gradients in fusion-grade plasmas provide free energy that may drive turbulence. The turbulence then enhances transport locally, leading to a local reduction of gradients and a consequential dampling of the turbulence amplitude. This feedback could be responsible for keeping the gradients below a critical value. Considered locally, the former is a description of a simple marginal state.
+The basic explanation for this phenomenon is self-regulation of the profiles by turbulence. The strong temperature and density gradients in fusion-grade plasmas provide free energy that may drive turbulence. The turbulence then enhances transport locally, leading to a local reduction of gradients and a consequential damping of the turbulence amplitude. This feedback could be responsible for keeping the gradients below a critical value. Considered locally, the former is a description of a simple marginal state.
 But the interaction of such feedback mechanisms on various radial locations would lead to ''avalanche'' behaviour and a true (scale-free) self-organised state.