Experimental study of ion sub-Larmor-scale turbulence by microwave scattering diagnostics developed at FT-2, DIII-D and NSTX tokamaks is reviewed. Peculiarities of electron temperature gradient (ETG) turbulence identification in dynamical experiments at these machines are discussed. The FT-2 experimental results concerning the role of the small-scale turbulence in the anomalous electron transport are compared with those published by DIII-D and NSTX teams. Possibilities of small-scale turbulence control by plasma rotation shear are discussed for marginal ETG turbulence in NSTX and FT-2.
Cross-scale interactions between turbulence driven by electron and ion temperature gradients via sub-ion-scale structures