Tokamak-edge toroidal rotation due to inhomogeneous transport and geodesic curvature
- Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany)
In a model kinetic ion transport equation for the pedestal and scrape-off layer, passing-ion drift orbit excursions interact with spatially inhomogeneous but purely diffusive transport to cause the orbit-averaged diffusivities to depend on the sign of {nu}{sub Parallel-To }, preferentially transporting counter-current ions for realistic parameter values. The resulting pedestal-top intrinsic rotation is typically co-current, reaches experimentally relevant values, and is proportional to pedestal-top ion temperature T{sub i} Double-Vertical-Line {sub pt} over plasma current I{sub p}, as observed in experiment. The rotation drive is independent of the toroidal velocity and its radial gradient, representing a residual stress. Co-current spin-up at the L-H transition is expected due to increasing T{sub i} Double-Vertical-Line {sub pt} and a steepening of the turbulence intensity gradient. A more inboard (outboard) X-point leads to additional co- (counter-) current rotation drive. Beyond intrinsic rotation, comparison of heat and momentum transport reveals that neutral beam injection must be significantly unbalanced in the counter-current direction to cause zero toroidal rotation at the pedestal top.
- OSTI ID:
- 22072378
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 5; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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