Observation of coherent sheared turbulence flows in the DIII-D Tokamak.

摘要: Time-resolved measurements of the turbulent density flow field in a tokamak plasma reveal low-frequency ($\ensuremath{\sim}15\text{ }\text{ }\mathrm{K}\mathrm{H}\mathrm{z}$), coherent oscillations poloidal flow, ${\stackrel{\texttildelow{}}{v}}_{\ensuremath{\theta}}$. These have long wavelength ($ml3$) and narrow radial extent (${k}_{r}{\ensuremath{\rho}}_{i}\ensuremath{\sim}0.2$). The estimated flow-shearing rate is same order magnitude as turbulence decorrelation may thus regulate amplitude. features are consistent with theoretically predicted axisymmetric, self-regulating, sheared flows recognized geodesic acoustic modes.