H. Nakanishi, M. Emoto, Y. Nagayama, T. Yamamoto, S. Imazu, C. Iwata, M. Kojima, M. Nonomura, M. Ohsuna, M. Yoshida, M. Hasegawa, A. Higashijima, K. Nakamura, Y. Ono, M. Shoji, S. Urushidani, M. Yoshikawa, K. Kawahata
Data Acquisition System for Steady State Experiments at Multi-Sites
Date of publication:
22 IAEA Fusion Energy Conference, FTP/P6-27
A high-performance data acquisition system (LABCOM system) has been developed for steady state fusion experiments in Large Helical Device (LHD). The most important characteristics of this system are the 110 MB/s high-speed real-time data acquisition capability and also the scalability on its performance by using unlimited number of data acquisition (DAQ) units. It can also acquire experimental data from multiple remote sites through the 1 Gbps fusion-dedicated virtual private network (SNET) in Japan. In LHD steady-state experiments, the DAQ cluster has established the world record of acquired data amount of 90 GB/shot which almost reaches the ITER data estimate. Since all the DAQ, storage, and data clients of LABCOM system are distributed on the local area network (LAN), remote experimental data can be also acquired simply by extending the LAN to the wide-area SNET. The speed lowering problem in long-distance TCP/IP data transfer has been improved by using an optimized congestion control and packet pacing method. Japan?France and Japan?US network bandwidth tests have revealed that this method actually utilize 90% of ideal throughput in both cases. Toward the fusion goal, a common data access platform is indispensable so that detailed physics data can be easily compared between multiple large and small experiments. The demonstrated bilateral collaboration scheme will be analogous to that of ITER and the supporting machines.