Results 1 - 10 of 2423
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[en] The Korea Superconducting Tokamak Advanced Research (KSTAR) is being majorly updated for 2010's operation which mainly aims to achieve the plasma shaping and diverted plasmas. The Plasma Facing Components (PFCs) such as inboard and outboard limiters, divertors, and passive stabilizers have been finally installed in the vacuum vessel (VV) by middle of June 2010. The baking and cooling (B and C) pipe system for all the PFCs were installed inside of the vacuum vessel to fulfill baking and active cooling of each PFC components. The PFCs are to be baked by circulating hot nitrogen gas through internal tubes of back-plates of the PFCs. While VV is baked-out, the PFCs temperature was raised from room temperature to 120 .deg. C, and the baking temperature was raised again to 200 .deg. C in spite of the VV being maintained at room temperature
[en] Geodesic acoustic modes (GAMs) in a tokamak excited by, for example, energetic particles can create a direct energy channel from energetic population to turbulence. In this paper, the ability of GAMs to further convert their energy into large scale motion such as zonal flows is investigated. The simplest case of GAMs, neglecting the effects of normal curvature, Alfven wave effect and drift effects, is considered. It is shown that such GAMs are stable with respect to generation of zonal flows.
[en] During the commissioning of the KSTAR device, electronic logbook has been developed to record participant's opinions regarding experimental procedures and results. The experimental logbook, a kind of the electronic logbooks inserts principal experimental parameters by itself and gets the experimenter's comments. Since it usually takes long time to surf around raw experimental data, a summarized comment on the experimental logbook helps physicists to analyze the results. The operation logbook, the other part of electronic logbook records history about system's abnormality, including their management history. Records on the operation logbook for components provide the criteria to validate the device's stability and the basis to complement the device operation procedure. Since a large majority of readers is interested in the information on the electronic logbook, the data is manipulated to be searched and read on the web-site which is accessible by the authenticated users. The web-site also includes a formatting function to report the logbook data as a document using Java Document Object Model (DOM) and Java Simple API for XML (SAX) API. Because there were difficulties to make an action scenario on the events due to insufficient experience of tokamak operation, it was developed in parallel during the commissioning. By training operators to write comments on every detail of the experimental results and operation events, it could be more valuable data source for the next experiments.
[en] Considerable progress has been made in research and development activities for the KSTAR magnetic diagnostics (MDs). Mirnov coil (MC) and diamagnetic loop (DL) as the KSTAR MDs were designed to diagnose magnetic instability at edge region and plasma stored energy, respectively, during plasma discharge in the KSTAR machine. The design features of MC and DL in the KSTAR and the technical issues on the fabrication and the installation of their prototypes are described
[en] In this paper, we measured plasma horizontal displacement using two experimental methods in the IR-T1 tokamak. First, two poloidal flux loops were designed and installed on the outer surface of the IR-T1 tokamak and were used to measure the Shafranov shift. Also, modified Rogowski and saddle sine coils based on the multipole moment method were designed, constructed and used. The results from these two methods are compared and are found to be in good agreement.