Speaker
Dr
June-Woo Juhn
(National Fusion Research Institute)
Description
Signals of vibrations are measured in different interferometers of Korea Superconducting Tokamak Advanced Research, KSTAR. The KSTAR device is equipped with three different interferometers. Millimeterwave (MMWI), far-infrared (FIRI) and two-color (TCI) whose viewing chords are all different : Horizontal, vertical and tangential way respectively. The mountings of each retro-reflector are also different. Center-stack concave mirror was installed for MMWI. And a reflector for FIRI was originally fixed under the 2.5m-long chimney inserted under a top-port (Gt), and later moved to outside vacuum vessel with specially designed compact-vibration-isolator (CVI). A reflector for TCI is installed on top of the vacuum vessel surface. The main vibration sources are major disruptions. It induces several seconds of large vibration signals in every interferometer including even MMWI. In addition, during the plasma discharge, the primary source of vibration is in-vessel-control-coil (IVCC). The IVCC takes load after 120ms to activate iso-flux control. This transition and influence of IVCC vibration is not observed in MMWI but clearly seen in both FIRI and TCI although the impact in FIRI has been reduced about 1/10 after installation of CVI and the most of vibrations are canceled with the operation of TCI.
The detail of the vibration level in relationship of IVCC and disruptions will be presented.
Primary author
Dr
June-Woo Juhn
(National Fusion Research Institute)
Co-authors
Mr
Hanmin Wi
(National Fusion Research Institute)
Dr
K. C. lee
(National Fusion Research Institute)
Mr
Y. S. Kim
(National Fusion Research Institute)
Dr
Y. U. Nam
(National Fusion Research Institute)
