A dependence of carbon impurity transport coefficients on fuel ions in hydrogen and helium plasmas of Large Helical Device

Journal Article · Fri Sep 15 04:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2337790· OSTI ID:20860243

Nozato, H; Morita, S; Goto, M; Takase, Y; Ejiri, A; Amano, T; Tanaka, K; Inagaki, S ^[1]

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1. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8563 (Japan)

Impurity transport of carbon has been studied using a new method combined carbon pellet injection with high-spatial resolution bremsstrahlung measurement on the Large Helical Device [A. Iiyoshi et al., Fusion Technol. 17, 169 (1990)]. The carbon pellets are injected into a steady phase in neutral beam heated discharges with a standard configuration of R{sub ax}=3.6 m. The particle transport coefficients (diffusion coefficient D and convective velocity V) are inferred using a diffusive/convective model. The results are compared between hydrogen and helium plasmas. As a result, it is found that the analyzed D has a constant radial profile with almost closed values of 0.2 m{sup 2}/s in both plasmas. On the other hand, the inward V is required only at the plasma outer region ({rho}>0.6) where the electron density gradient exits, and the inward V in helium plasmas (-0.4 m/s at {rho}=0.8 and n{sub e}{approx}4.0x10{sup 19} m{sup -3}) is nearly half as much as that in hydrogen plasmas (-0.7 m/s). This difference of the inward V between hydrogen and helium plasmas suggests a dependence on the charge state of fuel ions predicted from neoclassical theory.

• OSTI ID: 20860243
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 9 Vol. 13; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BREMSSTRAHLUNG
CARBON
CHARGE STATES
DIFFUSION
ELECTRON DENSITY
HELIUM
HYDROGEN
IONS
LHD DEVICE
NEOCLASSICAL TRANSPORT THEORY
PELLET INJECTION
PLASMA
PLASMA BEAM INJECTION
PLASMA CONFINEMENT
PLASMA DENSITY
PLASMA IMPURITIES
RADIATION TRANSPORT
SPATIAL RESOLUTION
STELLARATORS