UC Davis PDG:Sawteeth Observed on RTP

The spatial resolution of the ECEI system is demonstrated in the following figures obtained during ECRH with Ip=60 kA, ne=3.0x10e19 m-3. They are calibrated against the Te profiles measured by the double pulse Thomson scattering system on the same discharge. An m=2 mode is observed to be localized at the sawtooth inversion radius (r~3.5 cm), with a radial extent of less than 2 cm. This mode is very stable, which can survive the sawtooth crashes. The up-down symmetry of the mode verifies the accuracy of the measured channel positions. 

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For further technical details, and ECE Imaging measurements and results from RTP, please examine the following links: 

*Further technical details on the RTP ECE Imaging system
*Electron temperature fluctuation spectra
*Electron temperature fluctuation dispersion relations
*Electron temperature fluctuations as a function of plasma current and density
*2D structure of electron temperature fluctuations

The unique features of the ECE Imaging diagnostics derive from the use of wideband, low cost monolithic and hybrid Schottky diode mixer arrays. Follow the links below to learn more about both the technology and the techniques employed in ECE Imaging. 

*Imaging array design and fabrication
*Correlation Measurements

UC Davis has fabricated and installed multichannel ECE Imaging systems on other fusion plasma tokamaks across the world. Follow the links below for a description of the systems involved, and to sample data collected with these systems. 

*ECE Imaging on the TEXT-U tokamak in the U.S.A.
*ECE Imaging on the TEXTOR tokamak in Germany

email Comments to: Bihe Deng