Plasma turbulence characteristics, including radialcorrelation lengths, decorrelation times, amplitude profile and flowvelocity, have been measured during a ρ* scan on DIII-D while allother transport relevant dimensionless quantities (e.g., β, ν*, κ, q,Te/Ti) are held nearly constant. The turbulence is measured byexamining the correlation properties of the local long wavelength(k⊥ρi ⩽ 1) density fluctuations, measured with beam emissionspectroscopy. The radial correlation length of the turbulence Lc,ris shown to scale with the local ion gyroradius, Lc,r ≈ 5ρi,while the decorrelation times scale with the local acoustic velocityas τc∼a/cs. The turbulent diffusivity parameter, D∼(Lc,r2/τc), scalesin a roughly gyro-Bohm-like fashion, as predicted by the gyrokineticequations governing turbulent transport. The experimental one fluidpower balance heat diffusivity scaling and that from GLF23 modellingcompare reasonably well.
Scaling laws of density fluctuations at high-k on Tore Supra