Interplay between gyrokinetic turbulence, flows, and collisions: perspectives on transport and poloidal rotation.
The impact of ion-ion collisions on confinement is investigated with the full-f and global gyrokinetic Gysela code through a series of nonlinear turbulence simulations for tokamak parameters. A twofold scan in the turbulence drive and in collisionality is performed, highlighting (i) a heat transport expressed in terms of critical quantities-threshold and exponent, (ii) a first evidence of turbulent generation of poloidal momentum, and (iii) the dominance of mean flow shear, mediated through the turbulent corrugation of the mean profiles, with regard to the oft-invoked zonal flow shear.
Association Euratom-CEA, CEA/IRFM, F-13108 St. Paul-lez-Durance cedex, France.
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Dif-Pradalier
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Grandgirard
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Sarazin
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Garbet
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Ghendrih