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The application of large collection optics to image millimeter waves on a detector array improves the spatial resolution and enables the recovery of small-scale structures and fluctuation characteristics of the plasma electron temperature and density from radiometer and reflectometer measurements. Both diagnostic techniques are combined into a single instrument on the TEXTOR tokamak.

Wide RF bandwidth millimeter-wave antenna arrays are under development for plasma imaging applications. These quasi-optically coupled pumped arrays employ dual dipole antennas and wide IF bandwidth (1-10 GHz) baluns fabricated on low loss printed circuit boards, with biased surface mount Schottky diodes arranged in fundamental and subharmonic mixer form.

Dual dipole antennas have been developed in the frequency range of 33-50 GHz and 105-135 GHz for use as imaging array elements in an electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) plasma diagnostic system respectively. A wideband balun with less than 3 dB back to back insertion loss was achieved in the frequency range of 1.7 GHz-19.8 GHz (1:11.7) for convert IF signals from the balanced antenna to the unbalanced transmission line/connector.

Two dual dipole antennas have been designed in the frequency range of 85-95 GHz and 100-135 GHz for use as imaging array elements for magnetic fusion plasma microwave imaging reflectometry (MIR) and electron cyclotron emission imaging (ECEI) diagnostics, respectively. The antenna pattern is of primary importance for these applications, with emphasis on clean antenna patterns and low sidelobe levels for low interchannel crosstalk, tight channel spacing to minimize interchannel spacing in the plasma, and wide instantaneous bandwidth for real time 2D imaging. The extremely high temperature of the imaged plasma (>10 million degrees), means that a low receiver noise temperature is not critical as long as it is sufficiently low (/spl les/20000 degrees) to facilitate absolute calibration. The simulated and measured antenna patterns are presented in this paper.

Summary form only given. Diagnostic systems for fluctuation measurements in plasmas have, of necessity, evolved from simple 1-D systems to multi-dimensional systems due to the complexity of turbulence physics of plasmas in toroidal devices illustrated by advanced numerical simulations. Using the significant advancements in millimeter wave imaging technology, Microwave Imaging Reflectometry (MIR) and Electron Cyclotron Emission Imaging (ECEI), capable of simultaneously measuring density and temperature fluctuations are developed. Since both systems require large collection optics for the reflected waves from the "cut-off layer" in the MIR system and vertically (poloidally) extended emissions in ECEI system and since both systems operate in a similar microwave range in most of toroidal devices (e.g. the MIR frequency range is /spl sim/89 GHz and ECEI ranges from 95 to 130 GHz for TEXTOR), 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. The detailed testing of the optical system for MIR/ECEI was established with known targets (corrugated metal surfaces). The new 2-D ECE Imaging system (with a total of 128 channels), installed on TEXTOR in December, 2003, combines both techniques to provide a true 2-D imaging of T/sub e/ fluctuation such as "sawtooth crash" near q/spl sim/1 surface. In this paper, a brief review of the imaging diagnostics for turbulence study, combined MIR/ECEI system design description, laboratory testing details of the MIR/ECEI system and multichannel wideband IF technology are presented, together with the progress of subsequent experimental campaigns on TEXTOR plasmas.

A system capable of simultaneous 2-D imaging of electron density and temperature turbulence on TEXTOR is presently under development. Concept design details are presented. The system combines both electron temperature and density diagnostic techniques into a single instrument capable of the simultaneous measurement of both fluctuations (both turbulent and coherent) on the TEXTOR tokamak.

Summary form only given. An exciting tool for the study and visualization of plasma turbulence is presently under development for the TEXTOR-94 tokamak. This system combines a high resolution electron cyclotron emission imaging (ECEI) diagnostic with an innovative microwave imaging reflectometer (MIR) diagnostic for the simultaneous localized measurement of electron temperature T. and electron density n/sub e/ fluctuations in the tokamak core. The ECEI diagnostic images second harmonic cyclotron radiation from the optically thick plasma onto a 1-D array, thereby forming an image of the T/sub e/ profile and fluctuations associated with the emission layer. The MIR diagnostic images radiation reflected from the plasma cutoff layer onto a similar 1-D array, thus forming an image of n/sub e/ fluctuations at the reflecting layer. Both diagnostics are capable of forming 2-D images of plasma turbulence by varying the frequency of the probing (for MIR) or received (for ECEI) signals. Adjustment of the reflectometer probing frequency permits the reflecting layer to be positioned coincident with the ECEI emission layer, thereby simultaneously sampling both T/sub e/ and n/sub e/ fluctuations over an extended surface of the TEXTOR-94 plasma. Such data will permit the visualization of complicated 2-D and/or 3-D structures which is essential for definitive comparisons to be made with the predictions of gyrokinetic computer simulations. In addition, the system will also be employed in the study of a number of MM phenomena such as plasma filament formation, magnetic islands and internal transport barriers. An overview of the simultaneous imaging diagnostic concept will be presented along with technical details and characterization measurements of the TEXTOR-94 diagnostic. The system is presently under fabrication, and will begin operation in August, 2002 when TEXTOR-94 resumes operation after the installation of a dynamic ergodic divertor.