Turbulent Temperature Fluctuations in the Princeton Large Tokamak Plasma

We present the first experimental evidence for the existence of turbulent temperature fluctuations in plasmas. These measurements were accomplished by a spectral analysis of blackbody electron cyclotron emission. The fractional fluctuation in the mean electron energy is up to 10% for typical Princeton Large Tokamak discharges. The spectrum of temperature turbulence extends well beyond the electron diamagnetic-drift frequency f* and shows no resemblance to the simultaneously existing turbulent density fluctuations.