"Plasma and Fusion Cloud" Data analysis environment

ORCID　0000-0002-0441-6340The Fusion Cloud concept is currently underway at the National Institute for Fusion Science (NIFS). This concept is to deploy data collection and data analysis systems, which are assets developed through LHD experiments, to other laboratories in Japan through a high-speed network. The Open Data Server discussed in this paper is part of the Fusion Cloud concept, and data collected at LHD is currently being made publicly available. In the future, the data collected by various devices will be made widely available for use in fusion research, and will also be used for research beyond fusion and across different fields. In addition, in the future, not only the data but also a portable environment for analyzing these data will be provided on the cloud.journal articl

Impurity emission characteristics of long pulse discharges in Large Helical Device

Line spectra from intrinsic impurity ions have been monitored during the three kinds of long-pulse discharges (ICH, ECH, NBI). Constant emission from the iron impurity shows no preferential accumulation of iron ion during the long-pulse operations. Stable Doppler ion temperature has been also measured from Fe XX, C V and C III spectra

Improvement of Automatic Physics Data Analysis Environment for the LHD Experiment

The physical data of the Large Helical Device (LHD) project have been serviced by the Analyzed Data Server system, and approximately 600 kinds of physical data are served. In order to execute simulation programs for the LHD experiment, one must gather sets of physical data. Because the Automatic Analyzed Server (AutoAna) calculates the physical data automatically, it eases the scientist’s task of collecting these physical data. The AutoAna has provided better computing environments for the scientists. Thus, the scientists, having recognized its benefits, make various requests as issues arise. In this paper, the authors introduce the current status of the AutoAna system

NIFS Atomic and Molecular Numerical Database for Collision Processes

The National Institute for Fusion Science (NIFS) has compiled and developed atomic and molecular numerical databases for various collision processes and makes it accessible from the internet to the public. The database contains numerical data of cross sections and rate coefficients for electron collision or ion collisions with atoms and molecules, attached with bibliographic information on their data sources. The database system provides query forms to search data, and numerical data are retrievable. The graphical output is helpful to understand energy dependence of cross sections and temperature dependence of rate coefficients obtained by various studies. All data are compiled mainly from published literature, and data sources can be tracked by the bibliographic information. We also have data of sputtering yields and back-scattering coefficients for solid surfaces collided by ions in the database. All data in the database are applicable to understand atomic and molecular processes in various plasmas, such as fusion plasma, astrophysical plasma and applied plasma, as well as for understanding plasma–surface interaction in plasmas

Progress of “Plasma and Fusion Cloud” research data platform towards “Open Science”

ORCID　0000-0001-6388-4489A new cloud platform to realize the plasma and fusion experimental data ecosystem, named the “Plasma and Fusion Cloud,” has been technically verified on some fundamental issues. Such an enormous amount of diagnostic data requires a high-performance computing (HPC) platform not only for LHD physics data analyses but also for next-generation experiments, such as ITER and JT-60SA. Performance evaluation has been done at NIFS by using the HPC supercomputer “Raijin” and the LHD primary data storage system, both of which are directly connected by the 100 Gbps Ethernet optical link. The test results show that almost a full bandwidth can be used by means of multiple parallel streams. In order to make plasma and fusion diagnostic data “FAIR”, all the LHD’s diagnostic data objects are now under way to be registered with digital object identifiers (DOI) for each acquisition node and plasma pulse. In 2023, more than 1.2 million DOIs were issued for the LHD diagnostic data. Cloud technology is also very promising as a high-performance data computing platform, not only for physics data analyses but also for real-time plasma and plant controls. AWS (Amazon Web Service) S3 cloud storage has accepted a proposal to store all 2.0 peta-byte of compressed LHD physics data for open access, under the AWS Open Data Sponsorship Program (ODP). AWS is also one of the commercial providers of computing clouds in the framework of NII’s Research Data Cloud (RDC) in Japan, allowing LHD data users to increase or decrease the computing power they need on demand. The demonstrations and technical verifications done in this study suggest that a next-generation fusion data research center could be based on cloud technology.journal articl

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix

Inter-application communication during LHD consecutive short pulse discharge experiment

LHD short pulse experiments are executed every three minutes. After the end of the discharge, the scientists must collect, analyze, visualize the last acquired data of the discharge, and prepare for the next discharge. From the beginning, the computer environment of the LHD (Large Helical Device) experiment has been built as a network distributed system, and various computers have been used for data acquisition or physical analysis. When one program is finished on one computer, that computer must send the results in order to the other computers to run programs. Smooth communication is required in order to finish all the tasks before the next discharge. To exchange the information among the applications running on the different computers, the authors have tried various methods, such as a commercial software to share the memory over the network, simple network file sharing method, IP multicast, web interfaces, and others. The purpose of this paper is to share our experiences of trial and error to build the network distributed systems for the consecutive plasma discharge experiments

A patient with spontaneous rupture of the esophagus and concomitant gastric cancer whose life was saved: case of report and review of the literature in Japan

A 71-year-old man suddenly developed abdominal pain and vomiting on drinking soda after a meal, and visited a physician. Cervical subcutaneous and mediastinal emphysemas were observed on CT, and the patient was transferred to the emergency medical center of our hospital on the same day. Esophagography was performed at our department. A ruptured region was identified on the left side of the lower thoracic esophagus, and surgery was emergently performed employing sequential left thoracoabdominal incision. The chest wall was adhered due to inflammation, and large amounts of residual food and sloughing were present in the thoracic cavity and mediastinum. Moreover, necrotic changes were noted in the superior through inferior mediastinum. An about 2-cm rupture site was confirmed on the left side of the lower thoracic esophagus and closed by suture and filling with pediculate omentum. The presence of a tumorous lesion located mainly in the body of the stomach and lymph node enlargement were also diagnosed before surgery, for which gastric and intestinal fistulae were inserted to prepare for the second-stage surgery. The patient was admitted to an ICU after surgery. ARDS and MRSA-induced pneumonia and enteritis concomitantly developed but remitted. Curative surgery for gastric cancer was performed at 40 POD. Spontaneous rupture of the esophagus is relatively rare and that complicated by gastric caner is very rare, with only six cases being reported in Japan. Herein, we report the case

Extended capability of the integrated transport analysis suite, TASK3D-a, for LHD experiment

The integrated transport analysis suite, TASK3D-a (Analysis), has been developed to be capable for routine whole-discharge analyses of plasmas confined in three-dimensional (3D) magnetic configurations such as the LHD. The routine dynamic energy balance analysis for NBI-heated plasmas was made possible in the first version released in September 2012. The suite has been further extended through implementing additional modules for neoclassical transport and ECH deposition for 3D configurations. A module has also been added for creating systematic data for the International Stellarator–Heliotron Confinement and Profile Database. Improvement of neutral beam injection modules for multiple-ion species plasmas and loose coupling with a large-simulation code are also highlights of recent developments

W-band millimeter-wave back-scattering system for high wave number turbulence measurements in LHD

A 90 GHz W-band millimeter-wave back-scattering system is designed and installed for measuring electron scale turbulence (kρs ∼ 40). Ametal lens relay antenna is used for in-vessel beam focusing, and a beam diameter of less than 40mm is achieved in the plasma core region.This antenna can be steered at an angle of 159○ ± 6○, which almost covers the plasma radius. The estimated size of the scattering volume is ∼105mm at the edge and 135mm at the core, respectively. A 60m corrugated waveguide is used to achieve a low transmission loss of ∼8 dB. A heterodyne detection system for millimeter-wave circuits with probing power modulation can distinguish the scattered signal frombackground noise