ETG scale turbulence and transport in the DIII-D tokamak

Small-scale density turbulence (κperpendicularρi ∼ 4-10) and electron thermal transport are both observed to increase during electron cyclotron heating of a high temperature tokamak plasma (κperpendicular is the turbulent wavenumber and ρi the ion gyroradius). In contrast, large-scale turbulence (κperpendicularρi ≤ 1) and ion thermal transport remain effectively constant. This implies that the small-scale turbulence is not a remnant or tail of the ubiquitous, large-scale turbulence and also indicates a potentially important role in determining anomalous electron thermal transport. (author)