Spontaneous core toroidal rotation in Alcator C-Mod L-mode, H-mode and ITB plasmas
نویسندگان
چکیده
منابع مشابه
Observations of Toroidal Rotation Suppression with ITB Formation in ICRF and Ohmic H-mode Alcator C-Mod Plasmas
Co-current central toroidal rotation has been observed in Alcator C-Mod plasmas with on-axis ICRF heating. The rotation velocity increases with plasma stored energy and decreases with plasma current. Very similar behavior has been seen during Ohmic H-modes, which suggests that the rotation, generated in the absence of an external momentum source, is not principally an ICRF effect. A scan of the...
متن کاملImpurity toroidal rotation and transport in Alcator C-Mod ohmic h-mode plasmas
Central toroidal rotation and impurity transport coe cients have been determined in Alcator C-Mod Ohmic High Con nement Mode (H-mode) plasmas from observations of x-ray emission following impurity injection. Rotation velocities up to 3 10 m/s in the co-current direction have been observed in the center of the best Ohmic H-mode plasmas. Purely Ohmic H-mode plasmas display many characteristics si...
متن کاملH-mode edge stability of Alcator C-mod plasmas
For steady state H-mode operation, a relaxation mechanism is required to limit build-up of the edge gradient and impurity content. C-Mod sees two such mechanisms-EDA and grassy ELMs, but not large type I ELMs. In EDA the edge relaxation is provided by an edge localized quasicoherent electromagnetic mode that exists at moderate pedestal temperature T< 400 eV, high pedestal density and high edge ...
متن کاملH-mode Regimes and Observations of Central Toroidal Rotation in Alcator C-mod
The Enhanced Dα or EDA H-mode regime in Alcator C-Mod has been investigated and compared in detail to ELM-free plasmas. (In this paper, ELM-free will refer to discharges with no type I ELMs and with no sign of EDA, though technically, most EDA plasmas are ELM-free as well.) EDA discharges have only slightly lower energy confinement than comparable ELM-free ones, but show markedly reduced impuri...
متن کاملTheoretical interpretation of the toroidal rotation velocity observed in Alcator C-Mod Ohmic H-mode discharges
It is shown that neoclassical theory explains quite well the origin of the co-current toroidal rotation velocity measured in the core of stationary Alcator C-Mod edge localized mode (ELM)-free Ohmic high confinement (H)-mode discharges. Both edge and core toroidal rotation velocity profiles are determined to a good approximation by the edge ion temperature and density pedestals, where the gradi...
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ژورنال
عنوان ژورنال: Plasma Physics and Controlled Fusion
سال: 2008
ISSN: 0741-3335,1361-6587
DOI: 10.1088/0741-3335/50/12/124042