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We developed and installed an electron cyclotron emission radiometer for taking measurements of Korea Superconducting Tokamak Advanced Research (KSTAR) plasma. In order to precisely measure the absolute value of electron temperatures, a calibration measurement of the whole radiometer system was performed, which confirmed that the radiometer has an acceptably linear output signal for changes in input temperature. It was also found that the output power level predicted by a theoretical calculation agrees with that obtained by the calibration measurement. We also showed that the system displays acceptable noise-temperature performance around 0.23 eV. [ABSTRACT FROM AUTHOR]

A new probe set, called the Gundestrup-emissive-triple (GET) probe, is developed to measure the rotational velocity, plasma potential, electron temperature, and plasma density profiles simultaneously in Hanbit mirror device. The GET probe system is composed of the Gunderstrup, an emissive, and a triple probe installed in one boron nitride probe holder, which is attached on the fast scanning injection system. Rotational and parallel flow velocities are deduced from the measurement of Gundestrup probe by using fluid and kinetic theories for unmagnetized and magnetized plasmas. The E×B drift velocity is also deduced from the measurement of plasma potential by an emissive probe. Electron temperature and plasma density variations are measured by a triple probe. Applicability of various theories will be addressed. [ABSTRACT FROM AUTHOR]

Abstract: The KSTAR plasma facing components (PFCs) consist of inboard limiter, poloidal limiter, divertor, passive stabilizer and neutral beam armor. The main function of the PFCs is to define boundary of operating plasma and to protect the vacuum vessel and in-vessel components such as diagnostic components, in vessel control coil and several kinds of launchers for heating and current drive systems. The divertor is designed to enhance effective particle control to keep high quality plasma with various flexibilities in the shaping control for wide range of operational regime. The passive stabilizer that is made of CuCrZr alloy is designed to passively control the vertical position and MHD instabilities during operation as well as outer boundary of the plasma. Since fabrication has been started for all of the plasma facing components from middle of 2009, the inboard limiter, the divertor, and the passive stabilizer were successfully installed in the vacuum vessel, in turn. Moreover, one set of neutral beam armor and three strings of poloidal limiters were also installed according to the heating system that newly comes in 2010. All the PFCs tiles were baked to 200°C and the PFC system showed no vacuum leakage and other mechanical troubles. In this paper, key features, fabrication, results of assembly, and baking of the KSTAR PFCs are summarized in detail. [Copyright &y& Elsevier]

Abstract: In-vessel components of the Korea Superconducting Tokamak Advanced Research (KSTAR) were developed for 2010 campaign to provide a crucial circumstance for achieving the strongly shaped and diverted plasma. Moreover, the in-vessel components such as limiter, divertor, passive stabilizer, in-vessel control coil (IVCC) system demonstrated good performances satisfying the original design concepts. In addition to the plasma facing components and the IVCC, in-vessel cryo-pump (IVCP) system was also installed to leverage divertor operation. Besides the in-vessel components, there have been substantial progresses in development of the heating and current drive system. The KSTAR heating and current drive system includes all kinds of the major heating systems such as neutral beam injection (NBI), ion cyclotron range of frequency (ICRF), electron cyclotron resonance heating and current drive (ECH and ECCD), lower hybrid current drive (LHCD) systems. As an initial stage for full equipment of the heating systems to total power of 26MW, several key systems such as 1st NBI (called NBI-1), ICRF, and ECH-assisted startup system successfully demonstrated their excellent feasibilities in the design and performances for dedication to the 2010 campaign. [Copyright &y& Elsevier]

Abstract: An un-calibrated sensitive 3He detector was used to monitor the KSTAR neutron rate during Ohmically heated discharges. Neutrons were detected for every shot. If the neutrons were from D–D reactions then there should be a dependence on the ion temperature. We obtained ion temperature, electron density, Ohmic heating input power measurements, etc. from standard diagnostics. The study shows no observable dependence on the Ohmic power, ion temperature, or calculated source strength. It appears that the neutrons are from sources other than D–D reactions. The most probable source is high-energy runaway electrons. [Copyright &y& Elsevier]

Abstract: The optical diagnostic system of KSTAR consists of visible diagnostics including toroidal and poloidal Hα monitors, a visible survey spectrometer, and filterscopes. A re-entrant cassette made of stainless steel, containing five optical quartz windows has been developed to allow easy access of the visible diagnostics to the plasma. The configuration and manufacturing design of the diagnostic cassette and the installation of optical diagnostic systems within the cassette are described. The structural and thermal analysis of the diagnostic cassette and in situ calibration of optical diagnostics have also been performed. The optical lens system showed good image quality by spot diagram analysis. [Copyright &y& Elsevier]

Abstract: The time synchronization system (TSS) for KSTAR has been devised and is under development to support steady-state real time control for discharge operation, plasma diagnostics, and collection of a huge amount of data. The purpose of the system is to provide synchronized operation of all experiments according to the reference scenario, universal time for all the tokomak systems and appropriate time-stamping on all acquired data and events. The central timing system and local timing units, which comprise the time synchronization system, are connected via the dedicated optical time network. The TSS communicates via the giga-bit machine network for the provision of universal time, and uses the shared memory-based real-time network for real-time feedback control. A prototype timing modules has been developed and tested, it is based on the VME–bus standard and uses FPGA and micro-processors to implement the major functions such as time decoding, a 64-bit time counter, data processing, clock/pulse generation, etc. We are testing the pilot timing system with central and local timing units, and operated in an EPICS environment, the middleware program of the KSTAR control system. This paper presents features of KSTAR timing system and details of the developed prototype timing modules. [Copyright &y& Elsevier]