A long-pulse plasma discharge for more than 30 min.was achieved on the LargeHelical Device(LHD).A plasma of n_e=0.8×10^(19)m^(-3)and T_(iO)=2.0 keV was sustained withP_(ICH)=0.52 MW,P_(ECH)=0.1 MW and averaged P_...A long-pulse plasma discharge for more than 30 min.was achieved on the LargeHelical Device(LHD).A plasma of n_e=0.8×10^(19)m^(-3)and T_(iO)=2.0 keV was sustained withP_(ICH)=0.52 MW,P_(ECH)=0.1 MW and averaged P_(NBI)=0.067 MW.Total injected heatingenergy was 1.3 GJ,which was a quarter of the prepared RF heating energy.One of the keys to thesuccess of the experiment was a dispersion of the local plasma heat load to divertors,accomplishedby shifting the magnetic axis inward and outward.展开更多
Density modulation experiments are powerful experimental schemes for the study of particle transport. The diffusion coefficients （D） and convection velocity （V）, which cannot be evaluated from the particle balance...Density modulation experiments are powerful experimental schemes for the study of particle transport. The diffusion coefficients （D） and convection velocity （V）, which cannot be evaluated from the particle balance in the equilibrium state, can be obtained separately. Further, the estimated values of D and V are determined independent of the absolute value of the particle source rate, which is difficult to obtain experimentally. However, the sensitivities and interpretation of D and V from the modulation experiments need to be considered. This paper describes numerical techniques for solving the particle balance equation of the modulation components. Examples of the analysis are shown regarding the data of LHD experiments, and the results of the modulation experiments are discussed.展开更多
In the Large Helical Device （LHD）, two different divertor configurations, i.e. helical divertor （HD） and local island divertor （LID）, are utilized to control the edge plasma. The HD with two X-points is an intri...In the Large Helical Device （LHD）, two different divertor configurations, i.e. helical divertor （HD） and local island divertor （LID）, are utilized to control the edge plasma. The HD with two X-points is an intrinsic divertor for heliotron devices, accompanied with a relatively thick ergodic layer outside the confinement region. Edge and divertor plasma behavior from low density to high density regimes is presented, referring to the divertor detachment. The effect of the ergodic layer on the edge transport is also discussed. On the other hand, the LID is an advanced divertor concept which realizes a high pumping efficiency by the combination of an externally induced magnetic island and a closed pumping system. Experimental results to confirm the fundamental divertor performance of the LID are presented.展开更多
基金supported in part by the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘A long-pulse plasma discharge for more than 30 min.was achieved on the LargeHelical Device(LHD).A plasma of n_e=0.8×10^(19)m^(-3)and T_(iO)=2.0 keV was sustained withP_(ICH)=0.52 MW,P_(ECH)=0.1 MW and averaged P_(NBI)=0.067 MW.Total injected heatingenergy was 1.3 GJ,which was a quarter of the prepared RF heating energy.One of the keys to thesuccess of the experiment was a dispersion of the local plasma heat load to divertors,accomplishedby shifting the magnetic axis inward and outward.
基金supported in part by the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘Density modulation experiments are powerful experimental schemes for the study of particle transport. The diffusion coefficients （D） and convection velocity （V）, which cannot be evaluated from the particle balance in the equilibrium state, can be obtained separately. Further, the estimated values of D and V are determined independent of the absolute value of the particle source rate, which is difficult to obtain experimentally. However, the sensitivities and interpretation of D and V from the modulation experiments need to be considered. This paper describes numerical techniques for solving the particle balance equation of the modulation components. Examples of the analysis are shown regarding the data of LHD experiments, and the results of the modulation experiments are discussed.
基金supported by NIFS under Grant(No.NIFS05ULPP506)in part by the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘In the Large Helical Device （LHD）, two different divertor configurations, i.e. helical divertor （HD） and local island divertor （LID）, are utilized to control the edge plasma. The HD with two X-points is an intrinsic divertor for heliotron devices, accompanied with a relatively thick ergodic layer outside the confinement region. Edge and divertor plasma behavior from low density to high density regimes is presented, referring to the divertor detachment. The effect of the ergodic layer on the edge transport is also discussed. On the other hand, the LID is an advanced divertor concept which realizes a high pumping efficiency by the combination of an externally induced magnetic island and a closed pumping system. Experimental results to confirm the fundamental divertor performance of the LID are presented.
