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Author(s):
K. Ida, K. Itoh, S.-I. Itoh, S. Hidekuma and JIPP T-IIU & CHS Group
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Title:
Comparison of Toroidal/Poloidal Rotation in CHS Heliotron/Torsatron and JIPP T-IIU Tokamak
Date of publication:
Sep. 1990
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Key words:
plasma rotation, electric filed, neoclassical flux, tokamak, heliotron/torsatron
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Abstract:
Toroidal and poloidal rotation profiles have been measured on the JIPPT-IlU tokamak and CHS heliotron/torsatron devices with charge exchange recombination spectroscopy. Comparison of toroidal/poloidal rotation profiles between CHS and JIPPT-IlU is made for the L-mode plasmas. The parallel viscosity damping and anomalous radial transport of the momentum are studied. Comparison of electric field profiles inferred from plasma rotation and ion pressures also made. The plasma in CHS rotates poloidally near the plasma periphery and rotates toroidally at the center. The toroidal rotation velocity is localized at r < 0.3a , which is consistent with the estimate of neoclassical parallel viscosity due to helical ripples. The plasma in JIPPT-IIU rotates toroidally. The poloidal rotation is damped to less than a few km/s, which also supports neoclassical parallel viscous damping. The radial transport of toroidal rotation velocity on both devices is found to be anomalous and about 2-4 m^2/s. This value is comparable to the thermal diffusivity in JIPPT-IlU. The radial electric field in CHS has negative gradient (partial E_r/partial r < 0) , while the electric field in JIPPT-IlU has positive gradient (partial E_r/partial r > 0) near the plasma periphery. The relation of space potential to ion temperature is also discussed.
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