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Improved Data Acquisition Methods for Uninterrupted Signal Monitoring and Ultra-Fast Plasma Diagnostics in LHD

2012; Japan Society of Plasma Science and Nuclear Fusion Research; Volume: 7; Linguagem: Inglês

10.1585/pfr.7.2405007

1880-6821

H. Nakanishi, Setsuo Imazu, M. Ohsuna, Mamoru Kojima, M. Nonomura, M. Shoji, M. Emoto, Masanobu Yoshida, Chie Iwata, Hitoshi MIYAKE, Yoshio Nagayama, Kazuo Kawahata,

Advanced Data Storage Technologies

To deal with endless data streams acquired in LHD steady-state experiments, the LHD data acquisition system was designed with a simple concept that divides a long pulse into a consecutive series of 10-s “subshots”. Latest digitizers applying high-speed PCI-Express technology, however, output nonstop gigabyte per second data streams whose subshot intervals would be extremely long if 10-s rule was applied. These digitizers need shorter subshot intervals, less than 10-s long. In contrast, steady-state fusion plants need uninterrupted monitoring of the environment and device soundness. They adopt longer subshot lengths of either 10 min or 1 day. To cope with both uninterrupted monitoring and ultra-fast diagnostics, the ability to vary the subshot length according to the type of operation is required. In this study, a design modification that enables variable subshot lengths was implemented and its practical effectiveness in LHD was verified.