Momentum transport in the vicinity of q_min in reverse shear tokamaks due to ion temperature gradient turbulence

Abstract

We present an analytic study of momentum transport of tokamak plasmas in the vicinity of minimum safety factor (q) position in reversed magnetic shear configuration. Slab ion temperature gradient modes with an equilibrium flow profile are considered in this study. Quasi-linear calculations of momentum flux clearly show the novel effects of q-curvature on the generation of intrinsic rotation and mean poloidal flow without invoking reflectional symmetry breaking of parallel wavenumber (k k ). This q-curvature effect originates from the inherent asymmetry in k k populations with respect to a rational surface due to the quadratic proportionality of k k when q-curvature is taken into account. Discussions are made of possible implications of q-curvature induced plasma flows on internal transport barrier formation in reversed shear tokamaks. V C 2014 AIP Publishing LLC. [http://dx

ITB formation in gyrokinetic flux-driven ITG/TEM turbulence

“…This indicates that the position of ITB is sensitive not to the momentum source profile but to the q min surface, which is qualitatively consistent with the experimental observation that ITB is triggered inside the q min surface and evolved toward the q min surface [3,23]. The effect of reversed magnetic shear configuration on parallel momentum flux is also discussed in [24,25]. The novelty of this study is that the self-consistent mean flow coupled with the parallel flow triggers ITB formation in flux-driven toroidal ITG turbulence.…”

Effect of Sheared Magnetic Field on E × B Drift Instability in Plasma

“…If the mode frequency (𝜔) is sufficiently large compared to the E × B shearing rate, which is used for the quantitative assessment of the fluctuation suppression, then the above equation can be expressed as [25] 𝑅(𝑦)…”