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Total 4   
Research Achievements Development of KSTAR Data Integration System Main Contributor Taehyun Tak, KSTAR Inegrated Control Team Related Research Project KSTAR Device Operation Project Main Contributor Qualitative Achievements - Comparing time-synchronized data of KSTAR operation and experiment data - Supporting an integrated data path of KSTAR operation log (CMO, PCS Operation Log) - Providing index and basic data for initial shot analysis by newly building related services such as shot summary and operation schedule Quantitative Achievements - Publishing a paper (Fusion Engineering and Design) (SCI Index - Conceptual design of new data integration and process system for KSTAR data scheduling) - Development of data comparison and analysis service through user web service - Development of heterogeneous data integration access service Superiorities & differences Superiorities - Automated data processing and visualization services - Synchronization and integration services of heterogeneous data - Increasing operation availability through KSTAR operation information sharing system Differences - Provides integration of various services such as driving, schedule, experiment, initial shot analysis, etc. - Provides a foundation for applying technologies such as Big Data and Artificial Intelligence Expected Effect & Ripple Effect Technical Perspectives - Contribution to Plasma research through Shot Index search and information utilization - Possibility to apply artificial intelligence and other technologies by using various information Economical & Social Perspectives - Increasing KSTAR operational efficiency Evidence a Drawing of data integration system architecture User service screen Schedule Sharing Service screen
Research Achievements Experimental analysis and verification of characteristics and mechanism in natural ELM-free H-mode plasmas Main Contributor Jaehyun Lee, Young-Mu Jeon, Jayhyun Kim, Won-Ha Ko, Minwoo Kim, Yong-Un Nam (NFRI), Yongkyoon In, Hyeon K. Park (UNIST), Young-Chul Ghim, Jaewook Kim (KAIST) Related Research Project KSTAR joint experiment and plasma research Main Contributor Qualitative Achievements - Experimental verification of plasma fluctuation and perpendicular flow shear changes using 2D imaging diagnostics (ECEI, BES) for the characteristics and mechanism of quiescent H-mode (QH-mode) plasmas without external perturbation tools Quantitative Achievements - Provide a clue for the development of the QH-mode scenario through various measurement results and analysis, such as the presence of edge harmonic mode and interaction between the modes and the increase of plasma perpendicular flow shear Superiorities & differences Superiorities Improve the understanding of QH-mode plasma characteristics and mechanism using high-resolution 2D imaging diagnostics (ECEI, BES) to directly measure the electron temperature, density fluctuations, and perpendicular flow shear changes Differences - Experimental measurements of electron temperature, density fluctuations, and perpendicular flow shear, not simulation analysis based on profile changes, demonstrate the theory and principles of QH-mode plasma development. Expected Effect & Ripple Effect Technical Perspectives - Various KSTAR 2D imaging diagnostics were used to measure lots of physical quantities and utilized them for physics research to pursue the diversity of plasma physics research methods. This research method increased the understanding of the mechanism of QH-mode plasma Economical & Social Perspectives - If the edge-localized modes (ELMs) can be controlled naturally without external perturbation tools, it can be conducive to the plasma control technology, and longer lifetime of plasma facing components as well as improve the stability and confinement of the fusion plasma Evidence Characteristics of the QH-mode plasma observed by the 2D imaging diagnostics. The existence of edge harmonic modes and the increase of perpendicular flow shear are characterized.
Research Achievements Achievement of 90 seconds high-performance plasma operation in KSTAR Main Contributor H.-S. Kim / Senior Sci., Y.-M. Jeon / Principal Sci., S.H. Hahn / Principal Sci. Related Research Project KSTAR Joint Experiments and Plasma Research Main Contributor Qualitative Achievements - In order to develop high performance plasma technologies for longer plasma operation, the plasma operation scenario was optimized and it led to longer high-performance plasma operation of about 90 seconds (89.7 seconds) in 2018 compared to plasma operation of 72 seconds in 2017. - The optimization of real-time EFIT that reflects the characteristics of drifting magnetic diagnostic signal according to long plasma operation and the suggestion of optimal plasma shape for long plasma operation mitigated the gradual decrease of plasma performance in time and the thermal load of plasma facing components considered as issues for many years in terms of development of high-performance longer plasma operation technology. - It is not just limited to numerical increase of plasma operation time (72 seconds → 90 seconds), but at the same time provides a basis for pursuing excellence in plasma performance (maintaining performance). Quantitative Achievements - 1 paper in preparation (SCI), 2 international conference presentations (1 scheduled for April) Superiorities & differences Superiorities - Compared to 72 seconds of plasma operation time in 2017, it achieved in 90 seconds of plasma operation time in 2018. - For about 90 seconds, the electron temperature at the plasma core remained above 50 million degrees on average. - A method was proposed to mitigate the reduction of plasma performance degradation in time and the increase of PFCs thermal load. Differences - KSTAR 'high performance' longer plasma operation has world-class technique. Although China's EAST operates for about 100 seconds, its plasma performance was relatively lower than that of KSTAR. Expected Effect & Ripple Effect Technical Perspectives - High performance longer plasma operation technology is essential for commercializing fusion energy. There are still engineering challenges to be solved in order to operate the high performance plasma for more than hundreds of seconds. It is expected that KSTAR's high performance longer plasma operation will be based on solving many difficult nuclear fusion challenges that occur over a longer period of time. Economical & Social Perspectives - In terms of plasma performance, 'high performance' produces more fusion reactions and fusion energy, which is more beneficial economically. The ‘longer continuous operation’ of high performance plasma is essential for maintaining continuous fusion reactions in nuclear fusion reactors. Evidence 2018 High performance longer plasma operation experiment #21735 Real-time EFIT optimization to mitigate the gradual decrease of plasma performance in time (#21706 before optimization, #21735 after optimization) Reduction of the surface temperature growth of PFCs by suggestion of optimal shape for longer plasma operation
Research Achievements Maintains a core temperature of 100 million degrees for 1.5 s through the formation of an internal transport barrier (ITB) Main Contributor Jinil Chung, S. -H. Hahn and Advanced operation scenario research team Related Research Project KSTAR Joint experiments and plasma research (S. W. Yoon) Main Contributor Qualitative Achievements - Maintains a core temperature of 100 million degrees (~ 9 keV) for 1.5 s through the formation of an internal transport barrier (ITB) Quantitative Achievements - paper and conference presentation in preparation Superiorities & differences Superiorities - All physics parameters indicating plasma performance were very stable - It is likely to improve performance with the planned higher heating power Differences - The ion temperature reached about 100 million degrees and remained stable for the first time in a full superconducting tokamak Expected Effect & Ripple Effect Technical Perspectives - The ITB is concerned that it may provide a possible route towards simultaneous high fusion performance and continuous tokamak reactor operation in a non-inductive current drive state. - The access of the internal transport barrier (ITB) formation is dealt with an important physics issue in the most of major tokamaks Economical & Social Perspectives - An ignited reactor with ITB can be smaller and cheaper than a conventional reactor, if the ITB can be controlled and maintained in a stationary way Evidence Schematic of possible operation mode in a tokamak Time-trace parameters indicating plasma performance during the ITB Ion temperature profiles before (blue) and after (green) the ITB formation

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