UC Davis PDG:ECE Imaging on TEXTOR
UC Davis, in collaboration with the Princeton Plasma Physics Laboratory (PPPL) and the FOM Institute for Plasma Physics 'Rijnhuizen', have developed and installed on TEXTOR a combined ECE Imaging (ECEI) and Microwave Imaging Reflectometer (MIR) system. The ECE Imaging system collects second harmonic radiation emitted from the plasma, whose power is proportional to the plasma electron temperature at the emission layer. The MIR system illuminates the plasma with low power microwaves, and images reflections off the corresponding plasma “cut-off layer”.
Both systems operate in a similar microwave range, as the MIR frequency range is ~88 GHz and ECE Imaging ranges from 95 to 130 GHz. Consequently, it is feasible to combine the two systems which utilize state-of-the-art millimeter-wave planar imaging arrays positioned at the focal point of the detection system to form an image. Both MIR and ECE Imaging systems share large collection optics for the reflected waves from the “cut-off layer” and vertically (poloidally) extended emission, respectively. A simple beam splitter (not visible in the figure below) serves to split the combined signals to their respective imaging antenna arrays.
For further technical details, and ECE Imaging measurements and results from TEXTOR, please examine the following links:
The unique features of the ECE Imaging diagnostics derive from the use of wideband, low cost Schottky diode mixer arrays coupled with innovative, low cost electronics. Follow the links below to learn more about the technology employed in ECE Imaging.
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.