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
Runaway electrons in tokamaks have been widely studied theoretically and experimentally. The runaway confinement time τ1 in ohmic and additionally heated tokamak plasmas presents an anomalous behavior when compared w...Runaway electrons in tokamaks have been widely studied theoretically and experimentally. The runaway confinement time τ1 in ohmic and additionally heated tokamak plasmas presents an anomalous behavior when compared with theoretical predictions based on neoclassical models. Runaway electrons have received lately a great attention due to several reasons： （a） the possibility to study electromagnetic turbulence by measuring the runaway flux fluctuations and its energy spectra, and （ b ） the runaway electrons are powerful diagnostics capable of yielding valuable information on the actual distribution function of fusion experiments.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.
文摘Runaway electrons in tokamaks have been widely studied theoretically and experimentally. The runaway confinement time τ1 in ohmic and additionally heated tokamak plasmas presents an anomalous behavior when compared with theoretical predictions based on neoclassical models. Runaway electrons have received lately a great attention due to several reasons： （a） the possibility to study electromagnetic turbulence by measuring the runaway flux fluctuations and its energy spectra, and （ b ） the runaway electrons are powerful diagnostics capable of yielding valuable information on the actual distribution function of fusion experiments.
