New ECE diagnostics for the TEXTOR-94 tokamak

To aid the scientific research program on the Toroidal Experiment for Technology Oriented Research (TEXTOR)-94 tokamak, the existing electron cyclotron emission (ECE) diagnostics for the electron temperature studies are being extended with new systems that feature a good temporal and radial resolution. Using the possibility of obtaining the data on a fast time scale, ECE systems allow one to study fast phenomena like the dynamics of small-scale structures such as magnetic islands and transport barriers and microscopic temperature fluctuations throughout the plasma. The quantitative information about nonthermal electron populations can be obtained from the comparison of the second and third harmonic emission. A new 16-channel frequency tunable radiometer and a four-channel second harmonic system were recently installed at TEXTOR-94. The detailed description of the new TEXTOR-94 ECE systems and the recent results will be given and discussed in this article. (C) 2001 American Institute of Physics.