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Diagnostics upgrade in ET for stability and equilibrium studies.
| Author: | Gauvreau J.-L. |
| Coauthor: | T. A. Carter, P.-A. Gourdain, A. Grossman, D.J. LaFonteese, D. Pace, L. Schmitz, R.J. Taylor, A.E |
| Institution : | University of California at Los Angeles |
| Abstract text: | The goal of ET is to study the confinement and stability of the plasma near the beta limit, which has been reached in long pulse (5 sec) Ohmic plasmas. Using ICRF heating, ICCD and neutral beam injection as tools, we want to explore rotational stabilization and broad current profiles in order to avoid MHD modes leading to internal disruptions or loss of confinement.
ET has undergone a significant diagnostics upgrade. Many ports were added to the machine in order to install arrays for Bdot, SXR, VUV, neutral particle analysis, microwave interferometry, polarimetry and reflectometry. As a result, we will have the ability to collect relevant 1-D or 2-D information for the density profile , ion temperature profile, plasma current profile, rotation profiles, MHD modes and fluctuations. A tangential neutral beam is in place and a second one will be installed in the next few months. The Bdot coil arrays will allow the identification of mode numbers when instabilities occur, and therefore differentiate between internal kink, external kink and ballooning modes. The SXR chords will provide good temporal and spatial information and allow identification of low m modes. The SXR imaging will provide high resolution and identify high m modes. In addition to the magnetic flux measurements, central SXR tomography and polarimetry, will assist us in performing equilibrium reconstruction using different codes.
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