Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG

Spectra polarimetry of the motional stark effect at TEXTOR-94

The Balmer-alpha light emitted by neutral particles injected into tokamaks is polarized with respect to the Lorentz electric field experienced by these atoms: E-l = nu xB, known as the motional Stark effect (MSE). On TEXTOR-94 a new MSE system is under development which exploits the full spectral information, along with its polarization. The advantages of exploiting the full spectral information are obvious: beam velocity, observation volume, absolute value of B, the plasma radial electric field and the beam density can in principle all be extracted from the measurement, whereas the polarization can be detected as several lines simultaneously. The TEXTOR-94 MSE system consists of 30 radial channel, of which the full Balmer-alpha spectrum is measured at two orthogonal angles. This is accomplished by inserting a Glan-Laser prism in the optical path. All the optics is located inside the vessel to improve the radial resolution and minimize changes in polarization due to optical elements. Fibers transfer the light by a vacuum feedthrough towards a spectrometer. It is shown that the measured spectra can be adequately fitted. The accuracy for determining the safety factor q is estimated to be 10%-15% and for the radial electric field to be 30 kV/m. (C) 2001 American Institute of Physics

The motional stark effect diagnostic at TEXTOR-94

Knowledge of the current distribution in a tokamak is indispensable for an understanding of the energy transport in the plasma and controlling instabilities. A diagnostic exploiting the Motional Stark Effect (MSE) has the potential to obtain this quantity. This is based on a measurement of the polarisation of the Balmer-a light emitted by neutral particles injected into tokamaks. On the tokamak TEXTOR-94 a new MSE system is under development which exploits the full spectral information, along with its polarisation. This system consists of 30 radial channels, measuring the spectrum at two orthogonal angles. This is accomplished by inserting a Glan-Laser prism in the optical path. All the optics is housed in five camera modules and located inside the vessel to improve the radial resolution and minimise changes in polarisation due to optical elements. Fibres transfer the light by a vacuum feedthrough towards a spectrometer. The simple construction of the fibre feedthrough and its reliable operation opens the possibility to observe plasma light at all conceivable angles and positions, irrespective of suitable locations of windows. (C) 2001 Elsevier Science B.V. All rights reserved

Verifying elementary ITER maintenance actions with the MS2 benchmark product

A new facility has been taken in operation to investigate the influence of visual and haptic feedback on the performance of remotely executed ITER RH maintenance tasks. A reference set of representative ITER remote handling maintenance tasks was included the master slave manipulator system (MS2) benchmark product. The benchmark product was used in task performance tests in a representative two-handed dexterous manipulation test bed at NRG. In the setup, the quality of visual feedback was varied by exchanging direct view with indirect view setups in which visual feedback is provided via video cameras. Interaction forces were measured via an integrated force sensor. The impact of feedback quality on the performance of maintenance tasks at the level of handling individual parts was measured and analysed. Remote execution of the maintenance actions took roughly 3-5 times more time than hands-on. Visual feedback was identified as the dominant factor, including aspects like (lack of) operator control over camera placement, pan, tilt and zoom, lack of 3D perception, image quality, and latency. Haptic feedback was found to be important, but only in specific contact transition and constrained motion tasks. (C) 2011 Elsevier B.V. All rights reserved

A Fast Shutter Valve for Use in Plasma Diagnostics

A fast shutter valve, designed for operation in high-vacuum plasma physics experiments, is described. By electromagnetically induced movement of the shutter blade, opening and shutting times of the order of 10 ms have been achieved. The results of test measurements of the shutter velocity and of the gas resistance in the closed position are presented. Furthermore, the specific use of the shutter valve in a time-of-flight experiment is discussed

Analysis and validation center for ITER RH maintenance scenarios in a virtual environment

A facility for detailed simulation of maintenance processes in the ITER Hot Cell Facility (HCF) has been taken into operation. The facility mimics the Remote Handling (RH) work-cells as are presently foreseen. Novel virtual reality (VR) technology, extended with a physics engine is used to create a realistic setting in which a team of Remote Handling (RH) operators can interact with a virtual Hot Cell environment. The physics engine is used to emulate the Hot Cell behavior and to provide tactile feed-back of the (virtual) slave. Multi-operator maintenance scenarios can be developed and tested in virtual reality. Complex interactions between the RH operators and the HCF control system software will be tested. Task performance will be quantified and operational resource consumption will be estimated. (C) 2011 Elsevier B.V. All rights reserved