UC Davis PDG:ECE Imaging on TEXT-U

UC Davis, in collaboration with the University of Texas at Austin, installed an ECE Imaging system on the TEXT-U tokamak in Austin, Texas in September, 1995. This 20 channel system, shown schematically below, collected ECE Imaging data until the TEXT-U tokamak was shut down in December, 1995.
 
 

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The above figure shows the implementation of the TEXT-U ECE imaging system. Either a 89-99 GHz mechanically tunable Gunn Oscillator or a 90-119 GHz Backward Wave Oscillator (BWO) is used as the LO source. The dichroic plates prevent high power 60 GHz ECRH signals from reaching the array while permitting 2nd harmonic ECE signals to pass unimpeded. Lab tests show that the 1/e spot size at the focal plane ranged from 0.9 cm to 1.1 cm, and the channel spacing ranged from 1 cm to 1.6 cm, which are consistent with calculations. 

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

*2-D temperature profiles
*2-D temperature images
*Temperature profile evolution during sawteeth activity
*Temperature profile evolution during tearing mode activity
*Cross-correlation measurements of electron temperature fluctuations
*Temperature snakes observed during high power ECRH

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


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