Imaging of core electron temperature fluctuations of tokamak plasmas

Imaging techniques applied to plasma turbulence data have lead to the discovery of unexpected two-dimensional patterns in the fluctuation levels. The data are obtained in the core of tokamak plasmas, using the novel technique of correlation intensity interferometry. Low-frequency fluctuations, usually associated with tearing modes, are not only found as expected near the q = 2 surface, but also on the midplane outside this surface. Higher frequency fluctuations, usually associated with the drift wave family, are poloidally localized.