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The IBM instability, which follows the random seeding of the pre-processed pedestal profile in our computations, is very violent, growing for the nominal case at a rate Γ = 0 . 18 c$_{s}$/L$_{⊥}$ , just below the ideal interchange rate. On the other hand the growth curve Γ( t ) appears qualitatively the same as in basic turbulence cases. At all time points in the nonlinear phase Γ( t ) is well below its previous maximum. Just after initial saturation there is some nonlinear evolution in which Γ( t ) crosses zero before settling down into long-term statistical saturation. At late times the initial blowout no longer imprints the results: with a fixed source one merely finds bursty turbulence thereafter. Hence, there is no evidence for explosive instability in this nominal case, which, if present, would be visible in a finite time singularity in the fluctuating free energy E ∼ ( δf ) 2 ∼ ( t − t$_{crit}$ ) − p rising with a power p . 

The burst and the resulting decaying turbulence act to transport the pedestal plasma across the LCFS, where energy and particles are lost within short times by parallel boundary outflow to the scrape-off layer (SOL) limiter. Without maintenance of a heat and particle source at the core boundary, this leads to decay of the initial gradient with a rapid onset at the initial transition to nonlinearity at about t = 40. This time point also corresponds to the peak-flux time. 

However, the ion temperature profile already starts decaying during the low-amplitude linear growth phase, due to neoclassical (finite Larmor radius) transport (for detail on how 

