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UC
Davis PDG:ECE
Imaging on TEXT-U
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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.
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
Comments to: Calvin Domier