Abstract ▼

For successful operation of tokamak such as KSTAR and ITER, it is necessary to improve plasma confinement, which needs understanding fusion plasma transport. We will develop energy and particle transport diagnostics for KSTAR plasma and obtain experimental results, which lead to understanding plasma

For successful operation of tokamak such as KSTAR and ITER, it is necessary to improve plasma confinement, which needs understanding fusion plasma transport. We will develop energy and particle transport diagnostics for KSTAR plasma and obtain experimental results, which lead to understanding plasma transport phenomena. First, soft X-ray(SXR) tomography and tangential X-ray pinhole camera are expected to analyze energy transport from plasma core to edge region. Second, in order to analyze impurity emissivity data from vacuum ultra-violet(VUV) diagnostics, tomographic reconstruction code and impurity transport simulation code are to be developed. Third, advanced concept wave-cutoff diagnostics, which measures plasma fluctuation in KSTAR SOL region, are expected to investigate the physical phenomenon of ELM.

Research on plasma state in the edge of KSTAR plasma is important to understand plasma-wall interaction. Using floating harmonic method, electron temperature and ion flux can be measured. This method have been usually applied to processing plasma (low temperature plasma). The edge of KSTAR plasma is similar with processing plasma. Thus, we applied our measurement system to edge of KSTAR plasma. Experimental results showed reliability of our diagnostic system through comparison with data from other diagnostic method. And possibility of ELM detection was also presented. Oscillation of electron temperature was consistent with h-alpha emission data. In addition, study on measurement of thickness of dielectric material is also important to understand interaction between the plasma and wall. To measure dielectric thickness, we studied methodology of measurement. These research will be helpful for stable control of KSTAR plasma.

One of the objectives in this research is developing a code which analyzes and predicts various phenomena occurred in KSTAR plasmas such as micro-scale turbulence transport, neoclassical theory concerning particle collisions and magnetic field geometry, impurity transport and 3D field effect. It is necessary to develop this type of code taking account of KSTAR which is the only local machine generating large plasmas and consumes significant resources depending on certain experimental plans. Even though there have been some research and codes simulating plasmas locally or partly in Tokamak so far, the research on the code for integrated physics and analysis have been barely done. Therefore, in this project, we do develop a code which has capabilities to treat various temporal and spatial scales simultaneously and which is developed based on fundamental physics with minimal use of artificial model. Finally, trained man powers are expected through this project.

SXR tomography and tangential X-ray pinhole camera are key diagnostics for tokamak plasma energy trasport. SXR system with 64 channel AXUV detectors observes 2-dimensional image of soft X-ray emission from KSTAR plasma. In collaboration with FAR-TECH (U.S.A.), Ar Ross filter was added to it to observe Ar impurity behavior. In collaboration with ENEA(Italy), AXUV detectors were calibrated.

For X-ray pinhole camera, MWPC detectors with high time resolution and neutron durability are to be developed. Duplex MWPC detector with parallel readout system, which has improved time resolution, are expected to measure soft X-ray emission and electron temperature. Before KSTAR campaign, the optimization of X-ray pinhole camera and 2-dimensional image test with Fe-55 X-ray are scheduled. Based on these experiments, we join KSTAR campaign in 2011 for verification for the performance of duplex MWPC with parallel readout system.

For impurity study in KSTAR plasma, we introduce stand alone non-corona (SANCO) and modify it to fit KSTAR geometry. In addition, using KSTAR XICS diagnostics, it will conduct a study on impurity transport analysis. Based on accumulated tomographic techonology from soft X-ray diagnostics, reconstruction code are designed for KSTAR VUV spectrometer.

Wave cutoff probe are designed to have 10us time resolution, which is 100 times faster than existing probe diagnostics. In order to invent high temperature tolerance probe for tokamak plasma, various ceramic coatings are to be tested. This research includes not only developing, integrating, and improving the code but also applying it to other fusion devices as well as KSTAR. We mean developing codes here by minimizing use of artificial model or approximated methods and by being founded on first-principle. Integrating codes is a work process to connect each codes for interchange of their own information within one big circle and for simultaneous simulation. Improving code is a procedure to upgrade the developed code by comparison with other codes or introduction of new physical concepts. Lastly, applying codes is a procedure to use the developed code for real KSTAR geometry and to compare and analyze experimental results with the code products.


Soft X-ray diagnostics has been researched since 2009, and equipped with AXUV 64 channel detectors. With this diagnostics, soft X-ray emission was successfully measured and converted to 2-dimensional images in 2010, 2011 KSTAR campaign. Ar Ross filter, which has been developed in collaboration with FAR-TECH, allowed to observe temporal change of Ar impurity flux. In collaboration with ENEA (Italy), AXUV detectors were calibrated.

In X-ray pinhole camera research, 2-dimensional duplex MWPC with parallel readout system was first developed with high time resolution and neutron tolerance. For multichannel data processing, 200channel 100MS/s DAQ system has been developed. For optimization of TXPC, 2-dimensional imaging test was carried out with Fe-55 X-ray source. This diagnostics successfully measured soft X-ray emission in 2011 KSTAR campaign.

The signal calculated with SANCO code, which is based on transport coefficients in ASDEX-U, is well-matched with XICS diagnostic data. In addition, based on Ar impurity data from soft X-ray diagnostics, SANCO code successfully calculated Ar transport coefficients.

Wave-cutoff diagnostics 10-us time resolution was developed. It was test in helicon plasma device which generates high temperature magnetized plasma. High temperature tolerance probes with various ceramic coating were also tested.

We have developed the codes based on first-principle during this 3-year projects, and have simulated phenomena in various temporal and spatial scales by integrating with other codes. In addition, we have developed a 2-dimensional nonlinear collision module for the first time world-widely. With these developments, we have successfully applied to and simulated not only KSTAR but also other fusion devices.

We name the developed two codes as XGC1 and XGC0. XGC1 is a code to analyze turbulence transport in micro-scale. We have analyzed momentum transport and plasma rotation by this code. XGC0 is a simplified version of XGC1 for long-time simulation. We have used this code for researches on neoclassical theory in KSTAR, the influences of 3-dimensional magnetic perturbation, the effect of impurities, transport barriers, and edge physics.

We’d like to emphasize here that compared with other codes the both developed codes have remarkable features considering its foundation on first-principle and simulation of whole regions of Tokamak covering from core to edge. Furthermore, we have integrated XGC0 with other codes like M3D and ELITE, and have implemented nonlinear collision operator so that more accuracy of simulation is expected.

SXR diagnostics and X-ray pinhole camera are key diagnostics to study MHD instability and transport. With multi-filters, these diagnostics are able to measure electron temperature or analyze the behavior of specific neutrals. Multichannel signal processing programme and parallel type duplex MWPC are candidates for the new generation of X-ray imaging diagnostics.

The analysis with impurity transport simulation code contributes to the theoretical research such as MHD instability and turbulent transport. If the accuracy and calculation speed of VUV tomography code are improved, temporally varying impurity distribution in tokamak plasma would be observed.

Due to high time resolution, besides fusion plasma, wave cutoff probe is applicable for quickly varying plasma process. High temperature tolerance probe, which offer safety to plasma diagnostics, has potential for economic benefits from technology transfer to businesses.

Mainly, the developed and improved codes through this project will be used for analysis and prediction on experimental results of KSTAR. Even though we could not cross-compare our results with experimental results due to limitations of available data by deficiencies of necessary diagnostic devices in KSTAR, we expect the importance of our results would be getting increased as the diagnostic devices in KSTAR is being equipped more. In particular, we will use our code in analyzing various transport phenomena. Based on the simulation results, we can predict properties of advanced plasmas, minimize uncertainty of experiments, and optimize operational scenario. In addition, the developed codes can be easily applied to other fields like semi-conductor physics and solid-state physics considering its features based on first-principles. Lastly, the experienced skills through this project such as large-scale simulation and code integration can be used for computational physics and computer science helpfully.

(출처 : SUMMARY 10p)

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 요약서 ... 4
• 요약문 ... 6
• SUMMARY ... 10
• CONTENTS ... 15
• 목차 ... 16
• 제1장 연구개발과제의 개요 ... 17
• 1-1절. KSTAR 에너지 및 입자 수송과 불안정성 진단계 개발 및 해석 연구 ... 17
• 1-2절. KSTAR 내벽과 플라즈마 불안정성 모니터링을 위한 진단계 개발 ... 19
• 1-3절. KSTAR 플라즈마의 고급 통합 전산 모델링 및 해석 ... 23
• 제2장 국내외 기술개발 현황 ... 26
• 2-1절. KSTAR 에너지 및 입자 수송과 불안정성 진단계 개발 및 해석 연구 ... 26
• 2-2절. KSTAR 내벽과 플라즈마 불안정성 모니터링을 위한 진단계 개발 ... 31
• 2-3절. KSTAR 플라즈마의 고급 통합 전산 모델링 및 해석 ... 32
• 제3장 연구개발수행 내용 및 결과 ... 35
• 3-1절. KSTAR 에너지 및 입자 수송과 불안정성 진단계 개발 및 해석 연구 ... 35
• 3-2절. KSTAR 내벽과 플라즈마 불안정성 모니터링을 위한 진단계 개발 ... 186
• 3-3절. KSTAR 플라즈마의 고급 통합 전산 모델링 및 해석 ... 213
• 제4장 목표달성도 및 관련분야에의 기여도 ... 286
• 제5장 연구개발결과의 활용계획 ... 303
• 5-1절. KSTAR 에너지 및 입자 수송과 불안정성 진단계 개발 및 해석 연구 ... 303
• 5-2절. KSTAR 내벽과 플라즈마 불안정성 모니터링을 위한 진단계 개발 ... 305
• 5-3절. KSTAR 플라즈마의 고급 통합 전산 모델링 및 해석 ... 306
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ... 309
• 6-1절. KSTAR 에너지 및 입자 수송과 불안정성 진단계 개발 및 해석 연구 ... 309
• 6-2절. KSTAR 플라즈마의 고급 통합 전산 모델링 및 해석 ... 320
• 제7장 참고문헌 ... 324
• 끝페이지 ... 328